Cisco UCS Servers RAID Guide

Cisco UCS Servers RAID Guide

Updated: February 06, 2018

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Text Part Number: OL-26591-01

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Cisco UCS Servers RAID Guide

© 2015 Cisco Systems, Inc. All rights reserved.

					C O N T E N T S
	RAID Overview
C H A P T E R 1		1-1
	Information About RAID				1-1
	Drive Group			1-1
	Virtual Drive			1-1
	Disk Striping			1-2
	Disk Mirroring (RAID 1 and RAID 10) 1-2
	Parity	1-3
	Disk Spanning			1-3
	Hot Spares		1-4
	Global Hot Spare				1-5
	Dedicated Hot Spare 1-5
	Disk Rebuilds			1-6
	Hot Swap		1-6
	Drive States			1-7
	Virtual Drive States				1-7
	RAID Levels	1-8
	RAID Levels Summary				1-8
	RAID 0	1-9
	RAID 1	1-10
	RAID 5	1-10
	RAID 6	1-12
	RAID 00	1-13
	RAID 10	1-14
	RAID 50	1-15
	RAID 60	1-16

		Fault Tolerance 1-17
		Generic Drive Replacement Procedure		1-18
		Removing a Drive from a Server		1-18
		Installing a Drive in a Server	1-19
		Platform-Specific RAID and Drive Procedures 1-19
		Using Cisco Integrated Management Controller and Cisco UCS Server Configuration Utility for
C H A P T E R 2
		RAID Monitoring and Configuring	2-1
		Cisco Integrated Management Controller—Viewing Storage Properties 2-1
		Cisco UCS Server Configuration Utility—RAID Configuration 2-2
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Contents

C H A P T E R		3			Using Cisco UCS Manager for RAID Configuring and Monitoring 3-1
					Cisco UCS Manager Configuration				3-1
					Local Disk Configuration Policy					3-1
					Guidelines for all Local Disk Configuration Policies								3-2
					Guidelines for Local Disk Configuration Policies Configured for RAID 3-3
					Creating a Local Disk Configuration Policy						3-4
					Changing a Local Disk Configuration Policy						3-6
					Deleting a Local Disk Configuration Policy						3-7
					Server Disk Drive Monitoring			3-7
					Support for Disk Drive Monitoring					3-7
					Viewing the Status of a Disk Drive					3-8
					Interpreting the Status of a Monitored Disk Drive							3-9
					RAID Controllers in UCS Servers				3-10
					Determining Which Controller is in Your Server							3-11
					RAID Controllers 3-12
					Disabling Quiet Boot		3-12
					Accessing ROM-Based Controller Utilities						3-13
					Documentation About RAID Controllers and LSI Utilities								3-13
					Moving a RAID Cluster Using UCS Software Version 1.4(1) 3-13
					Moving a RAID Cluster Using UCS Software Version 1.4(2) and Later Releases 3-14
					Moving a RAID Cluster Between B200 M3 Servers							3-15
					Replacing a Failed Drive in a RAID Cluster						3-16
					Configuring the LSI SAS2 Integrated RAID Controller
C H A P T E R		4										4-1
					Information about LSI Integrated RAID					4-1
					Mirrored Volumes	4-3
					Operation of Mirrored Volumes 4-3
					Mirrored Volume Features			4-6
					Mirroring and Mirroring Enhanced Features						4-7
					Integrated Striping	4-8
					Integrated Striping Features				4-9
					Creating Mirrored Volumes		4-10
					Launching the LSI SAS2 BIOS Configuration Utility								4-10
					Creating Mirrored Volumes				4-11
					Creating an Integrated Mirroring Volume 4-11
					Creating an Integrated Mirroring Enhanced or Integrated Mirroring and Striping Volume 4-13
					Expanding an Integrated Mirroring Volume with OCE								4-14
					Managing Hot Spare Disks				4-15
					Creating Hot Spare Disks				4-15
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Contents

Deleting Hot Spare Disks 4-15
Other Configuration Tasks	4-16
Viewing Volume Properties		4-16
Running a Consistency Check		4-16
Activating an Array	4-17
Deleting an Array 4-17

Locating Disk Drives in a Volume			4-18
Choosing a Boot Disk	4-18
Creating Integrated Striping Volumes		4-19
Other Configuration Tasks	4-21
Viewing Volume Properties		4-21
Activating an Array	4-21
Deleting an Array 4-21
Locating Disk Drives in a Volume			4-22
Choosing a Boot Disk	4-23

	Determining Which Controller is in Your Server				4-23
	Disabling Quiet Boot for CIMC Firmware Earlier than Release 1.2(1) 4-24
	Launching Option ROM-Based Controller Utilities				4-24
	Restoring RAID Configuration After Replacing a RAID Controller 4-25
	LSI MegaRAID SAS Controller Tasks
C H A P T E R 5				5-1
	LSI MegaRAID Controller Management Utilities				5-1
	LSI WebBIOS Configuration Utility			5-1
	MegaRAID Command Tool		5-2
	MegaRAID Storage Manager 5-2
	LSI WebBIOS CU	5-2
	Starting the WebBIOS CU		5-2
	WebBIOS CU Main Menu Window Options				5-3
	Toolbar 5-4
	Menu Options	5-4

	Configuring RAID Drive Groups and Virtual Drives 5-5
	Choosing the Configuration with the Configuration Wizard		5-5
	Using Automatic Configuration	5-5
	Using Manual Configuration	5-6
	Viewing and Changing Device Properties 5-11
	Viewing Controller Properties	5-11
	Viewing Virtual Drive Properties, Policies, and Operations		5-13
	Viewing Physical Drive Properties and Operations 5-14
	Viewing and Changing Battery Backup Unit Information		5-15
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Contents

Managing RAID	5-16
Expanding a Virtual Drive		5-16
Monitoring Array Health		5-16
Recovery	5-17

Deleting a Virtual Drive 5-18
Migrating an Array to a New Server		5-18
Foreign Configurations in Cable Pull and Drive Removal Scenarios				5-19
Importing Foreign Configurations from Integrated RAID to MegaRAID 5-20
Troubleshooting Information		5-20
Migrating the RAID Level of a Virtual Drive			5-20
Determining Which Controller is in Your Server			5-22
Disabling Quiet Boot for CIMC Firmware Earlier than Release 1.2(1)				5-22
Launching an Option ROM-Based Controller Utility 5-22
LSI MegaRAID Card Beep Codes		5-23
Restoring the RAID Configuration After Replacing a RAID Controller				5-23
Limitation on Importing Foreign Configuration To a Virtual Disk That is Under Construction 5-25
Limitation	5-25
Design	5-25

	Prerequisites For Reconstruction to Start	5-26
	Configuring the Embedded ICH10R SATA Controller
C H A P T E R 6			6-1
	Enabling the Integrated Intel ICH10R RAID Controller in the BIOS 6-1
	Launching the LSI Software RAID Setup Utility		6-1
	Configuring the Onboard Intel ICH10R RAID Controller		6-2
	Creating a New RAID Configuration	6-3
	Viewing or Changing a RAID Configuration		6-4

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C H A P T E R 1

RAID Overview

This chapter describes RAID (Redundant Array of Independent Disks), RAID functions and benefits, RAID components, RAID levels, and configuration strategies.

This chapter contains the following sections:

•Information About RAID, page 1-1

•RAID Levels, page 1-8

•Generic Drive Replacement Procedure, page 1-18

•Platform-Specific RAID and Drive Procedures, page 1-19

Information About RAID

RAID is an array, or group, of multiple independent physical drives that provide high performance and fault tolerance. A RAID drive group improves input/output (I/O) performance and reliability. The RAID drive group appears to the host computer as a single storage unit or as multiple virtual units. I/O is expedited because several drives can be accessed simultaneously.

RAID drive groups improve data storage reliability and fault tolerance compared to single-drive storage systems. Data loss resulting from a drive failure can be prevented by reconstructing missing data from the remaining drives. RAID improves I/O performance and increases storage subsystem reliability.

RAID levels describe a system for ensuring the availability and redundancy of data stored on large disk subsystems. See RAID Levels, page 1-8 for detailed information about RAID levels. The RAID drive-group components and RAID levels are described in the following sections.

Drive Group

A drive group is a group of physical drives. These drives are managed in partitions known as virtual drives.

Virtual Drive

A virtual drive is a partition in a drive group that is made up of contiguous data segments on the drives. A virtual drive can consist of an entire drive group, more than one entire drive group, a part of a drive group, parts of more than one drive group, or a combination of any two of these conditions.

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Chapter 1 RAID Overview

Information About RAID

Disk Striping

Disk striping (used in RAID level 0) allows you to write data across multiple drives instead of only one drive. Disk striping involves partitioning each drive storage space into stripes that can vary in size from 8 KB to 1024 KB. These stripes are interleaved in a repeated sequential manner. The combined storage space is composed of stripes from each drive. We recommend that you keep stripe sizes the same across RAID drive groups.

For example, in a four-disk system using only disk striping, segment 1 is written to disk 1, segment 2 is written to disk 2, and so on (see Figure 1-1). Disk striping enhances performance because multiple drives are accessed simultaneously, but disk striping does not provide data redundancy

Figure 1-1 Example of Disk Striping (RAID 0)

Segment 1	Segment 2	Segment 3	Segment 4
Segment 5	Segment 6	Segment 7	Segment 8
Segment 9	Segment 10	Segment 11	Segment 12

332084

Stripe width is the number of drives involved in a drive group where striping is implemented. For example, a four-disk drive group with disk striping has a stripe width of four.

The stripe size is the length of the interleaved data segments that the RAID controller writes across multiple drives, not including parity drives. For example, consider a stripe that contains 64 KB of disk space and has 16 KB of data residing on each disk in the stripe. In this case, the stripe size is 64 KB and the strip size is 16 KB.

The strip size is the portion of a stripe that resides on a single drive.

Disk Mirroring (RAID 1 and RAID 10)

With disk mirroring (used in RAID 1 and RAID 10), data written to one drive is simultaneously written to another drive. The primary advantage of disk mirroring is that it provides 100 percent data redundancy. Because the contents of the disk are completely written to a second disk, data is not lost if one disk fails. In addition, both drives contain the same data at all times, so either disk can act as the operational disk. If one disk fails, the contents of the other disk can be used to run the system and reconstruct the failed disk.

Disk mirroring provides 100 percent redundancy but is expensive because each drive in the system must be duplicated (see Figure 1-2).

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Information About RAID

Figure 1-2 Example of Disk Mirroring (RAID 1)

Segment 1

Segment 2

Segment 3

Segment 4

Parity

Segment 1 Duplicated

Segment 2 Duplicated

Segment 3 Duplicated

Segment 4 Duplicated

332085

Parity generates a set of redundancy data from two or more parent data sets. The redundancy data can be used to reconstruct one of the parent data sets in the event of a drive failure. Parity data does not fully duplicate the parent data sets, but parity generation can slow the write process. In RAID, this method is applied to entire drives or stripes across all of the drives in a drive group. There are two types of parity:

•Dedicated parity—The parity data on two or more drives is stored on an additional disk.

•Distributed parity—The parity data is distributed across more than one drive in the system.

RAID 5 combines distributed parity with disk striping (see Figure 1-3). If a single drive fails, it can be rebuilt from the parity and the data on the remaining drives. RAID 5 uses parity to provide redundancy for one drive failure without duplicating the contents of entire drives. RAID 6 uses distributed parity and disk striping also but adds a second set of parity data so that it can survive up to two drive failures.

Note Parity is distributed across all drives in the drive group.

Figure 1-3 Example of Distributed Parity (RAID 5)

Segment 1	Segment 2	Segment 3	Segment 4	Segment 5	Parity (1–5)
Segment 7	Segment 8	Segment 9	Segment 10	Parity (6–10)	Segment 6
Segment 13	Segment 14	Segment 15	Parity (11–15)	Segment 11	Segment 12
Segment 19	Segment 20	Parity (16–20)	Segment 16	Segment 17	Segment 18
Segment 25	Parity (21–25)	Segment 21	Segment 22	Segment 23	Segment 24
Parity (26–30)	Segment 26	Segment 27	Segment 28	Segment 29	Segment 30

332086

Disk Spanning

Disk spanning allows multiple drives to function like one big drive. Spanning overcomes lack of disk space and simplifies storage management by combining existing resources or adding relatively inexpensive resources. For example, four 20-GB drives can be combined to appear to the operating system as a single 80-GB drive.

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Information About RAID

Spanning alone does not provide reliability or performance enhancements. Spanned virtual drives must have the same stripe size and must be contiguous. In Figure 1-4, RAID 1 drive groups are turned into a RAID 10 drive group.

Note Make sure that the spans are in different backplanes, so that if one span fails, you do not lose the whole drive group.

Figure 1-4 Example of Disk Spanning

60 GB

60 GB

60 GB

60 GB

Can be accessed as

Can be accessed as

one 120-GB drive

one 120-GB drive

332087

Spanning two contiguous RAID 0 virtual drives does not produce a new RAID level or add fault tolerance. It does increase the capacity of the virtual drive and improves performance by doubling the number of physical disks.

Table 1-1 describes how to configure RAID 00, RAID 10, RAID 50, and RAID 60 by spanning. The virtual drives must have the same stripe size and the maximum number of spans is eight. The full drive capacity is used when you span virtual drives; you cannot specify a smaller drive capacity.

Table 1-1 Spanning for RAID 00, RAID 10, RAID 50, and RAID 60

RAID

Level Description

00Configure RAID 00 by spanning two contiguous RAID 0 virtual drives, up to the maximum number of supported devices for the controller.

10Configure RAID 10 by spanning two contiguous RAID 1 virtual drives, up to the maximum number of supported devices for the controller.

RAID 10 supports a maximum of eight spans. You must use an even number of drives in each RAID virtual drive in the span.

The RAID 1 virtual drives must have the same stripe size.

50 Configure RAID 50 by spanning two contiguous RAID 5 virtual drives.

The RAID 5 virtual drives must have the same stripe size.

60Configure RAID 60 by spanning two contiguous RAID 6 virtual drives. The RAID 6 virtual drives must have the same stripe size.

Hot Spares

A hot spare is an extra, unused drive that is part of the disk subsystem. It is usually in standby mode, ready for service if a drive fails. If a drive used in a RAID virtual drive fails, a hot spare automatically takes its place and the data on the failed drive is rebuilt on the hot spare. Hot spares can be used for RAID levels 1, 5, 6, 10, 50, and 60.

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Information About RAID

Hot spares permit you to replace failed drives without system shutdown or user intervention. MegaRAID SAS RAID controllers can implement automatic and transparent rebuilds of failed drives using hot spare drives, providing a high degree of fault tolerance and zero downtime.

Note When running RAID 0 and RAID 5 virtual drives on the same set of drives (a sliced configuration), a rebuild to a hot spare cannot occur after a drive failure until the RAID 0 virtual drive is deleted.

The LSI RAID management software allows you to specify drives as hot spares. When a hot spare is needed, the RAID controller assigns the hot spare that has a capacity closest to and at least as great as that of the failed drive to take the place of the failed drive. The failed drive is removed from the virtual drive and marked ready awaiting removal once the rebuild to a hot spare begins. You can make hot spares of the drives that are not in a RAID virtual drive.

You can use the RAID management software to designate the hot spare to have enclosure affinity, which means that if drive failures are present on a split backplane configuration, the hot spare is used first on the backplane side that it resides in.

If the hot spare is designated as having enclosure affinity, it attempts to rebuild any failed drives on the backplane that it resides in before rebuilding any other drives on other backplanes.

Note If a rebuild to a hot spare fails for any reason, the hot spare drive is marked as failed. If the source drive fails, both the source drive and the hot spare drive is marked as failed.

There are two types of hot spares:

•Global hot spare

•Dedicated hot spare

Global Hot Spare

A global hot spare drive can be used to replace any failed drive in a redundant drive group as long as its capacity is equal to or larger than the capacity of the failed drive. A global hot spare defined on any channel should be available to replace a failed drive on both channels.

Dedicated Hot Spare

A dedicated hot spare can be used to replace a failed drive only in a chosen drive group. One or more drives can be designated as a member of a spare drive pool. The most suitable drive from the pool is chosen for failover. A dedicated hot spare is used before one from the global hot spare pool.

Hot spare drives can be located on any RAID channel. Standby hot spares (not being used in RAID drive group) are polled every 60 seconds at a minimum, and their status is made available in the drive group management software. RAID controllers offer the ability to rebuild with a disk that is in a system, but not initially set to be a hot spare.

When using hot spares, observe the following guidelines:

•Hot spares are used only in drive groups with redundancy, which includes RAID levels 1, 5, 6, 10, 50, and 60.

•A hot spare connected to a specific RAID controller can be used to rebuild a drive that is connected to the same controller only.

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Information About RAID

•You must assign the hot spare to one or more drives through the controller BIOS or use drive group management software to place it in the hot spare pool.

•A hot spare must have free space equal to or greater than the drive it replaces. For example, to replace an 18-GB drive, the hot spare must be 18 GB or larger.

Disk Rebuilds

When a drive in a RAID drive group fails, you can rebuild the drive by recreating the data that was stored on the drive before it failed. The RAID controller recreates the data using the data stored on the other drives in the drive group. Rebuilding can be done only in drive groups with data redundancy, which includes RAID 1, 5, 6, 10, 50, and 60 drive groups.

The RAID controller uses hot spares to rebuild failed drives automatically and transparently, at user-defined rebuild rates. If a hot spare is available, the rebuild can start automatically when a drive fails. If a hot spare is not available, the failed drive must be replaced with a new drive so that the data on the failed drive can be rebuilt.

The failed drive is removed from the virtual drive and marked ready awaiting removal when the rebuild to a hot spare begins. If the system goes down during a rebuild, the RAID controller automatically restarts the rebuild after the system reboots.

Note When the rebuild to a hot spare begins, the failed drive is often removed from the virtual drive before management applications detect the failed drive. When this situation occurs, the events logs show the drive rebuilding to the hot spare without showing the failed drive. The formerly failed drive is marked as ready after a rebuild begins to a hot spare.

Note If a source drive fails during a rebuild to a hot spare, the rebuild fails, and the failed source drive is marked as offline. In addition, the rebuilding hot spare drive is changed back to a hot spare. After a rebuild fails because of a source drive failure, the dedicated hot spare is still dedicated and assigned to the correct drive group, and the global hot spare is still global.

An automatic drive rebuild does not start if you replace a drive during a RAID-level migration. The rebuild must be started manually after the expansion or migration procedure is complete. (RAID-level migration changes a virtual drive from one RAID level to another.)

Hot Swap

A hot swap is the manual replacement of a defective drive unit while the computer is still running (performing its normal functions). When a new drive is installed, a rebuild occurs automatically if one of the following happens:

•The newly inserted drive is the same capacity as or larger than the failed drive.

•It is placed in the same drive bay as the failed drive it is replacing.

The RAID controller can be configured to detect the new drives and rebuild the contents of the drive automatically. The backplane and enclosure must support hot swap for the functionality to work.

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Information About RAID

Drive States

A drive state is a property that indicates the status of the drive. Table 1-2 describes the drive states.

Table 1-2	Drive States
State		Description
Online		A drive that can be accessed by the RAID controller and is part of the virtual drive.
Unconfigured		A drive that is functioning normally but is not configured as a part of a virtual drive
Good		or as a hot spare.
Hot Spare		A drive that is powered up and ready for use as a spare in case an online drive fails.
Failed		A drive that was originally configured as Online or Hot Spare but on which the
		firmware detects an unrecoverable error.
Rebuild		A drive to which data is being written to restore full redundancy for a virtual drive.
Unconfigured		A drive on which the firmware detects an unrecoverable error; the drive was
Bad		Unconfigured Good or the drive could not be initialized.
Missing		A drive that was Online but which has been removed from its location.
Offline		A drive that is part of a virtual drive but which has invalid data as far as the RAID
		configuration is concerned.
		When a virtual drive with cached data goes offline, the cache for the virtual drive is
		discarded. Because the virtual drive is offline, the cache cannot be saved.

Virtual Drive States

A virtual drive state is a property indicating the status of the virtual drive. Table 1-3 describes the virtual drive states.

Table 1-3	Virtual Drive States
State		Description
Optimal		The virtual drive operating condition is good. All configured drives are online.
Degraded		The virtual drive operating condition is not optimal. One of the configured drives has
		failed or is offline.
Partial		The operating condition in a RAID 6 virtual drive is not optimal. One of the
Degraded		configured drives has failed or is offline. RAID 6 can tolerate up to two drive failures.
Failed		The virtual drive has failed.
Offline		The virtual drive is not available to the RAID controller.

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RAID Levels

RAID Levels

The MegaRAID controller supports RAID levels 0, 00, 1, 5, 6, 10, 50, and 60. It also supports independent drives (configured as RAID 0 and RAID 00.) The supported RAID levels are summarized in the following section.

RAID Levels Summary

•RAID 0 uses striping to provide high data throughput, especially for large files in an environment that does not require fault tolerance.

•RAID 1 uses mirroring so that data written to one drive is simultaneously written to another drive which is good for small databases or other applications that require small capacity, but complete data redundancy.

•RAID 5 uses disk striping and parity data across all drives (distributed parity) to provide high data throughput, especially for small random access.

•RAID 6 uses distributed parity, with two independent parity blocks per stripe, and disk striping. A RAID 6 virtual drive can survive the loss of two drives without losing data. A RAID 6 drive group, which requires a minimum of three drives, is similar to a RAID 5 drive group. Blocks of data and parity information are written across all drives. The parity information is used to recover the data if one or two drives fail in the drive group.

•A RAID 00 drive group is a spanned drive group that creates a striped set from a series of RAID 0 drive groups.

•RAID 10, a combination of RAID 0 and RAID 1, consists of striped data across mirrored spans. A RAID 10 drive group is a spanned drive group that creates a striped set from a series of mirrored drives. RAID 10 allows a maximum of eight spans. You must use an even number of drives in each RAID virtual drive in the span. The RAID 1 virtual drives must have the same stripe size. RAID 10 provides high data throughput and complete data redundancy but uses a larger number of spans.

•RAID 50, a combination of RAID 0 and RAID 5, uses distributed parity and disk striping. A RAID 50 drive group is a spanned drive group in which data is striped across multiple RAID 5 drive groups. RAID 50 works best with data that requires high reliability, high request rates, high data transfers, and medium-to-large capacity.

Note You cannot have virtual drives of different RAID levels, such as RAID 0 and RAID 5, in the same drive group. For example, if an existing RAID 5 virtual drive is created out of partial space in an array, the next virtual drive in the array has to be RAID 5 only.

•RAID 60, a combination of RAID 0 and RAID 6, uses distributed parity, with two independent parity blocks per stripe in each RAID set, and disk striping. A RAID 60 virtual drive can survive the loss of two drives in each of the RAID 6 sets without losing data. It works best with data that requires high reliability, high request rates, high data transfers, and medium-to-large capacity.

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RAID Levels

RAID 0

RAID 0 provides disk striping across all drives in the RAID drive group. RAID 0 does not provide any data redundancy but does offer the best performance of any RAID level. RAID 0 breaks up data into smaller segments and stripes the data segments across each drive in the drive group. The size of each data segment is determined by the stripe size. RAID 0 offers high bandwidth.

Note RAID level 0 is not fault tolerant. If a drive in a RAID 0 drive group fails, the whole virtual drive (all drives associated with the virtual drive) will fail.

By breaking up a large file into smaller segments, the RAID controller can use both SAS drives and SATA drives to read or write the file faster. RAID 0 involves no parity calculations to complicate the write operation, which makes RAID 0 ideal for applications that require high bandwidth, but do not require fault tolerance. Table 1-4 provides an overview of RAID 0. Figure 1-5 shows an example of a RAID 0 drive group advantage.

Table 1-4	RAID 0 Overview
Feature		Description
Uses		Provides high data throughput, especially for large files. Any environment that does
		not require fault tolerance.
Benefits		Provides increased data throughput for large files.
		No capacity loss penalty for parity.
Limitations		Does not provide fault tolerance or high bandwidth.
		All data is lost if any drive fails.
Drives		1 to 32.
Figure 1-5	RAID 0 Drive Group Example

Segment 1	Segment 2
Segment 3	Segment 4
Segment 5	Segment 6
Segment 7	Segment 8

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RAID Levels

RAID 1

In RAID 1, the RAID controller duplicates all data from one drive to a second drive in the drive group. RAID 1 supports an even number of drives from 2 to 32 in a single span. RAID 1 provides complete data redundancy but at the cost of doubling the required data storage capacity. Table 1-5 provides an overview of RAID 1. Figure 1-6 shows an example of a RAID 1 drive group.

Table 1-5

RAID 1 Overview

Feature

Description

Uses

Use RAID 1 for small databases or any other environment that requires fault

tolerance, but small capacity.

Benefits

Provides complete data redundancy. RAID 1 is ideal for any application that requires

fault tolerance and minimal capacity.

Limitations

Requires twice as many drives. Performance is impaired during drive rebuilds.

Drives

2 to 32 (must be an even number of drives).

Figure 1-6

RAID 1 Drive Group Example

Segment 1

Segment 1

Segment 2

Segment 2

Segment 3

Segment 3

Duplicate

Duplicate

Duplicate

Segment 5

Segment 5

Segment 6

Segment 6

Segment 7

Duplicate

Duplicate

Segment 7 Duplicate

...

...

...

RAID1

RAID1

RAID1

Segment 4 SegmentDuplicate4

Segment 8 SegmentDuplicate8

...

332089

RAID1

RAID 5

RAID 5 includes disk striping at the block level and parity. Parity is the property of the data of being odd or even, and parity checking is used to detect errors in the data. In RAID 5, the parity information is written to all drives. RAID 5 is best suited for networks that perform a lot of small input/output (I/O) transactions simultaneously. RAID 5 provides data redundancy, high read rates, and good performance in most environments. It also provides redundancy with the lowest loss of capacity.

In addition, RAID 5 is good for any application that has high read request rates but has low write request rates.

RAID 5 addresses the congestion issue for random I/O operations. Because each drive contains both data and parity, numerous writes can take place concurrently.

Table 1-6 provides an overview of RAID 5. Figure 1-7 shows an example of a RAID 5 drive group.

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RAID Levels

Table 1-6	RAID 5 Overview
Features		Description
Uses		Provides high data throughput, especially for large files. Use RAID 5 for transaction
		processing applications because each drive can read and write independently. If a
		drive fails, the RAID controller uses the parity drive to recreate all missing
		information. Use also for office automation and online customer service that requires
		fault tolerance. Use for any application that has high read request rates but low write
		request rates.
Benefits		Provides data redundancy, high read rates, and good performance in most
		environments. RAID 5 provides redundancy with the lowest loss of capacity.
Limitations		Not well-suited to tasks that require a large number of writes. RAID 5 has problems
		if no cache is used (clustering). The drive’s performance is reduced if a drive is being
		rebuilt. Environments with few processes do not perform as well because the RAID
		overhead is not offset by the performance gains in handling simultaneous processes.
Drives		3 to 32.

Note Parity is distributed across all drives in the drive group.

Figure 1-7 RAID 5 Drive Group Example

Segment 1	Segment 2	Segment 3	Segment 4	Segment 5	Parity (1–5)
Segment 7	Segment 8	Segment 9	Segment 10	Parity (6–10)	Segment 6
Segment 13	Segment 14	Segment 15	Parity (11–15)	Segment 11	Segment 12
Segment 19	Segment 20	Parity (16–20)	Segment 16	Segment 17	Segment 18
Segment 25	Parity (21–25)	Segment 21	Segment 22	Segment 23	Segment 24
Parity (26–30)	Segment 26	Segment 27	Segment 28	Segment 29	Segment 30

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RAID Levels

RAID 6

RAID 6 is similar to RAID 5 (disk striping and distributed parity), except that instead of one parity block per stripe, there are two. With two independent parity blocks, RAID 6 can survive the loss of two drives in a virtual drive without losing data. RAID 6 provides a high level of data protection through the use of a second parity block in each stripe. Use RAID 6 for data that requires a very high level of protection from loss.

RAID 6 is best suited for networks that perform a lot of small input/output (I/O) transactions simultaneously. It provides data redundancy, high read rates, and good performance in most environments.

In the case of a failure of one drive or two drives in a virtual drive, the RAID controller uses the parity blocks to recreate all of the missing information. If two drives in a RAID 6 virtual drive fail, two drive rebuilds are required, one for each drive. These rebuilds do not occur at the same time. The controller rebuilds one failed drive and then the other failed drive.

Table 1-7 provides an overview of a RAID 6 drive group. Figure 1-8 shows a RAID 6 data layout. The second set of parity drives are denoted by Q. The P drives follow the RAID 5 parity scheme.

Table 1-7	RAID 6 Overview
Features		Description
Uses		Use for office automation and online customer service that requires fault tolerance.
		Use for any application that has high read request rates but low write request rates.
Benefits		Provides data redundancy, high read rates, and good performance in most
		environments, can survive the loss of two drives or the loss of a drive while another
		drive is being rebuilt, and provides the highest level of protection against drive
		failures of all of the RAID levels. The read performance is similar to that of RAID 5.
Limitations		Not well-suited to tasks that require a large number of writes. A RAID 6 virtual drive
		has to generate two sets of parity data for each write operation, which results in a
		significant decrease in performance during writes. The drive performance is reduced
		during a drive rebuild. Environments with few processes do not perform as well,
		because the RAID overhead is not offset by the performance gains in handling
		simultaneous processes. RAID 6 costs more because of the extra capacity required
		by using two parity blocks per stripe.
Drives		3 to 32.

Note Parity is distributed across all drives in the drive group.

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RAID Levels

Figure 1-8 RAID 6 Drive Group Example

Segment 1	Segment 2	Segment 3	Segment 4	Parity (P1–P4)	Parity (Q1–Q4)
Segment 6	Segment 7	Segment 8	Parity (P5–P8)	Parity (Q5–Q8)	Segment 5
Segment 11	Segment 12	Parity (P9–P12)	Parity (Q9–Q12)	Segment 9	Segment 10
Segment 16	Parity (P13–P16)	Parity (Q13–Q16)	Segment 13	Segment 14	Segment 15
Parity (P17–P20)	Parity (Q17–Q20)	Segment 17	Segment 18	Segment 19	Segment 20

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RAID 00

A RAID 00 drive group is a spanned drive group that creates a striped set from a series of RAID 0 drive groups. RAID 00 does not provide any data redundancy, but along with RAID 0, RAID 00 offers the best performance of any RAID level. RAID 00 breaks up data into smaller segments and stripes the data segments across each drive in the drive groups. The size of each data segment is determined by the stripe size. RAID 00 offers high bandwidth.

Note RAID level 00 is not fault tolerant. If a drive in a RAID 0 drive group fails, the whole virtual drive (all drives associated with the virtual drive) fails.

By breaking up a large file into smaller segments, the RAID controller can use both SAS drives and SATA drives to read or write the file faster. RAID 00 involves no parity calculations to complicate the write operation, which makes RAID 00 ideal for applications that require high bandwidth but do not require fault tolerance. Table 1-8 provides an overview of RAID 00. Figure 1-9 shows an example of a RAID 00 drive group.

Table 1-8	RAID 00 Overview
Features		Description
Uses		Provides high data throughput, especially for large files. Use RAID 00 in any
		environment that does not require fault tolerance.
Benefits		Provides increased data throughput for large files. RAID 00 has no capacity loss
		penalty for parity.
Limitations		Does not provide fault tolerance or high bandwidth. All data is lost if any drive fails.
Drives		Two to the maximum number of drives that are supported by the controller.

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RAID Levels

Figure 1-9 RAID 00 Drive Group Example Using Two Drives

RAID 00

Segment 1

Segment 2

Segment 3

Segment 4

Segment 5

Segment 6

Segment 7

Segment 8

Segment 9

Segment 10

Segment 11

Segment 12

Segment 13

Segment 14

Segment 15

Segment 16

Segment 17 Segment 18

Segment 19

Segment 20

Segment 21

Segment 22

Segment 23

Segment 24

...

...

...

...

RAID 0

RAID 0

RAID 0

RAID 0

RAID 0

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RAID 10

RAID 10 is a combination of RAID 0 and RAID 1 and consists of stripes across mirrored drives. RAID 10 breaks up data into smaller blocks and mirrors the blocks of data to each RAID 1 drive group. The first RAID 1 drive in each drive group then duplicates its data to the second drive. The size of each block is determined by the stripe size parameter, which is set during the creation of the RAID set. The RAID 1 virtual drives must have the same stripe size.

Spanning is used because one virtual drive is defined across more than one drive group. Virtual drives defined across multiple RAID 1 level drive groups are referred to as RAID level 10, (1+0). Data is striped across drive groups to increase performance by enabling access to multiple drive groups simultaneously.

Each spanned RAID 10 virtual drive can tolerate multiple drive failures, as long as each failure is in a separate drive group. If there are drive failures, less than the total drive capacity is available.

Configure RAID 10 by spanning two contiguous RAID 1 virtual drives, up to the maximum number of supported devices for the controller. RAID 10 supports a maximum of eight spans with a maximum of 32 drives per span. You must use an even number of drives in each RAID 10 virtual drive in the span.

Note Other factors, such as the type of controller, can restrict the number of drives supported by RAID 10 virtual drives.

Table 1-9 provides an overview of RAID 10. In Figure 1-10, virtual drive 0 is created by distributing data across four RAID 1 drive groups (drive groups 0 through 3).

Table 1-9 RAID 10 Overview

				Benefits	Description
				Uses	Appropriate when used with data storage that needs 100 percent redundancy of
					mirrored drive groups and that also needs the enhanced I/O performance of RAID 0
					(striped drive groups.) RAID 10 works well for medium-sized databases or any
					environment that requires a higher degree of fault tolerance and moderate to medium
					capacity.
				Benefits	Provides both high data transfer rates and complete data redundancy.
				Limitations	Requires twice as many drives as all other RAID levels except RAID 1.
				Drives	Two to 8 equal spans of RAID 1 drive groups containing 2 to 32 drives each (limited
					by the maximum number of devices supported by the controller). You must use an
					even number of drive spans.
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RAID Levels

Figure 1-10 RAID 10 Virtual Drive Example

RAID 10

Segment 1

Segment 1

Segment 2

Segment 2

Segment 3

Segment 3

Segment 4

Segment 4

Duplicate

Duplicate

Duplicate

Duplicate

Segment 5

Segment 5

Segment 6

Segment 6

Segment 7

Segment 7

Segment 8

Segment 8

Duplicate

Duplicate

Duplicate

Duplicate

...

...

...

...

RAID1

RAID1

RAID1

RAID1

RAID 0

332143

RAID 50

RAID 50 provides the features of both RAID 0 and RAID 5. RAID 50 includes both parity and disk striping across multiple drive groups. RAID 50 is best implemented on two RAID 5 drive groups with data striped across both drive groups.

RAID 50 breaks up data into smaller blocks and stripes the blocks of data to each RAID 5 disk set. RAID 5 breaks up data into smaller blocks, calculates parity, and writes the blocks of data and parity to each drive in the drive group. The size of each block is determined by the stripe size parameter, which is set during the creation of the RAID set.

RAID level 50 can support up to eight spans and tolerate up to eight drive failures though less than total drive capacity is available. Though multiple drive failures can be tolerated, only one drive failure can be tolerated in each RAID 5 level drive group.

Table 1-10 provides an overview of RAID 50. In Figure 1-11, virtual drive 0 is created by distributing data across two RAID 5 drive groups.

Table 1-10	RAID 50 Overview
Features		Description
Uses		Appropriate when used with data that requires high reliability, high request rates,
		high data transfer, and medium to large capacity.
Benefits		Provides high data throughput, data redundancy, and very good performance.
Limitations		Requires 2 to 8 times as many parity drives as RAID 5.
Drives		Two to 8 equal spans of RAID 5 drive groups containing 3 to 32 drives each (limited
		by the maximum number of devices supported by the controller.)

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RAID Levels

Figure 1-11 RAID 50 Virtual Drive Example

RAID 50

Segment 1

Segment 2

(Segment 1,2)

Segment 3

Segment 4

(Segment 3,4)

Segment 6

(Segment 5,6)

Segment 5

Segment 8

(Segment 7,8)

Segment 7

(Segment 9,10) Segment 9

Segment 10

(Segment 11,12) Segment 11 Segment 12

RAID 5

RAID 5

RAID 0

332097

RAID 60

RAID 60 provides the features of both RAID 0 and RAID 6 and includes both parity and disk striping across multiple drive groups. RAID 6 supports two independent parity blocks per stripe. A RAID 60 virtual drive can survive the loss of two drives in each of the RAID 6 sets without losing data. RAID 60 is best implemented on two RAID 6 drive groups with data striped across both drive groups.

RAID 60 breaks up data into smaller blocks and stripes the blocks of data to each RAID 6 disk set. RAID 6 breaks up data into smaller blocks, calculates parity, and writes the blocks of data and parity to each drive in the drive group. The size of each block is determined by the stripe size parameter, which is set during the creation of the RAID set.

RAID 60 can support up to 8 spans and tolerate up to 16 drive failures though less than total drive capacity is available. Two drive failures can be tolerated in each RAID 6 level drive group.

Table 1-11 provides an overview of RAID 60. Figure 1-12 shows a RAID 6 data layout. The second set of parity drives are denoted by Q. The P drives follow the RAID 5 parity scheme.

Table 1-11	RAID 60 Overview
Features		Description
Uses		Provides a high level of data protection through the use of a second parity block in
		each stripe. Use RAID 60 for data that requires a very high level of protection from
		loss.
		In the case of a failure of one drive or two drives in a RAID set in a virtual drive, the
		RAID controller uses the parity blocks to recreate all of the missing information. If
		two drives in a RAID 6 set in a RAID 60 virtual drive fail, two drive rebuilds are
		required, one for each drive. These rebuilds can occur at the same time.
		Use for office automation and online customer service that requires fault tolerance.
		Use for any application that has high read request rates but low write request rates.
Benefits		Provides data redundancy, high read rates, and good performance in most
		environments. Each RAID 6 set can survive the loss of two drives or the loss of a
		drive while another drive is being rebuilt. RAID 60 provides the highest level of
		protection against drive failures of all of the RAID levels. The read performance is
		similar to that of RAID 50, though random reads in RAID 60 might be slightly faster
		because data is spread across at least one more disk in each RAID 6 set.

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RAID Levels

Table 1-11	RAID 60 Overview (continued)
Features		Description
Limitations		Not well suited to tasks using many writes. A RAID 60 virtual drive has to generate
		two sets of parity data for each write operation, which results in a significant decrease
		in performance during writes. Drive performance is reduced during a drive rebuild.
		Environments with few processes do not perform as well because the RAID overhead
		is not offset by the performance gains in handling simultaneous processes. RAID 6
		costs more because of the extra capacity required by using two parity blocks per
		stripe.
Drives		Two to 8 equal spans of RAID 6 drive groups containing 3 to 32 drives each (limited
		by the maximum number of devices supported by the controller.)

Note Parity is distributed across all drives in the drive group.

Figure 1-12 RAID 60 Virtual Drive Example

RAID 60

Segment 1	Segment 2	Parity (Q1–Q2)	Parity (P1–P2)		Segment 3	Segment 4	Parity (Q3–Q4)	Parity (P3–P4)
Segment 8	Parity (Q3–Q4)	Parity (P3–P4)	Segment 7		Segment 6	Parity (Q5–Q6)	Parity (P5–P6)	Segment 5
Parity (Q11–Q12)	Parity (P11–P12)	Segment 11	Segment 12		Parity (Q9–Q10)	Parity (P9–P10)	Segment 9	Segment 10
Parity (P15–P16)	Segment 15	Segment 16	Parity (Q15–Q16)		Parity (P13–P14)	Segment 13	Segment 14	Parity (Q13–Q14)
	RAID 6					RAID 6

RAID 0

332098

Fault Tolerance

Fault tolerance is the capability of the subsystem to undergo a drive failure or failures without compromising data integrity and processing capability. The RAID controller provides this support through redundant drive groups in RAID levels 1, 5, 6, 10, 50, and 60. The system can operate properly even with a drive failure in a drive group, although performance might be degraded to some extent.

•A RAID 1 drive group has two drives and can tolerate one drive failure.

•A RAID 5 drive group can tolerate one drive failure in each RAID 5 drive group.

•A RAID 6 drive group can tolerate up to two drive failures.

•Each spanned RAID 10 virtual drive can tolerate multiple drive failures as long as each failure is in a separate drive group.

•A RAID 50 virtual drive can tolerate two drive failures as long as each failure is in a separate drive group.

•RAID 60 drive groups can tolerate up to two drive failures in each drive group.

Note RAID level 0 is not fault tolerant. If a drive in a RAID 0 drive group fails, the whole virtual drive (all drives associated with the virtual drive) fails.

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Chapter 1 RAID Overview

Generic Drive Replacement Procedure

Fault tolerance is often associated with system availability because it allows the system to be available during the failures. However, it is also important for the system to be available during the repair of the problem.

Hot spares are important in fault tolerance; see Hot Spares, page 1-4 for more information.

Auto-rebuild allows a failed drive to be replaced and the data automatically rebuilt by hot swapping the drive in the same drive bay. See Hot Swap, page 1-6 for more information. The RAID drive group continues to handle requests while the rebuild occurs.

Generic Drive Replacement Procedure

Note B-series blade servers are shown but the mechanical features (release button, eject lever) are the same for most B-series and C-series servers.

Removing a Drive from a Server

Step 1 Push the button to release the ejector, fully extend the ejection lever and then pull the hard drive from its slot. See Figure 1-13.

Figure 1-13 Removing the Drive

Step 2 Place the hard drive on an antistatic mat or antistatic foam if you are not immediately reinstalling it in another blade server.

Step 3 Install a blank faceplate (N20-BBLKD) to keep dust out of the server if the slot will remain empty.

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Platform-Specific RAID and Drive Procedures

Installing a Drive in a Server

Step 1 Place the hard drive lever into the open position by pushing the release button (see Figure 1-14).

Figure 1-14 Installing a Hard Drive in a Blade Server

Step 2 Gently slide the hard drive into the opening in the blade server until it seats into place.

Step 3 Push the hard drive lever into the closed position.

If you need to move a RAID cluster, see the Moving a RAID Cluster section of the “Troubleshooting Server Hardware” chapter of the Cisco UCS Troubleshooting Guide.

Platform-Specific RAID and Drive Procedures

B-series RAID and supported drive information that was previously in the software configuration, hardware installation and service, and troubleshooting guides is repeated in this guide. B series servers all have onboard RAID controllers that cannot be removed or upgraded. Only software configuration and drive operations appropriate for that server’s controller are possible.

Supported RAID controllers for all models are listed in RAID Controllers in UCS Servers, page 3-10.

The C-Series hardware installation guides each have a “RAID Considerations” appendix that provides information about supported RAID controllers and cables, plus cabling instructions specific to each server model. See that documentation as needed at:

http://www.cisco.com/en/US/products/ps10493/prod_installation_guides_list.html

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Platform-Specific RAID and Drive Procedures

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C H A P T E R 2

Using Cisco Integrated Management Controller and Cisco UCS Server Configuration Utility for RAID Monitoring and Configuring

This chapter provides information about monitoring and configuring your RAID controller in your Cisco Integrated Management Controller (CIMC) and Cisco UCS Server Configuration Utility. The Cisco C-Series servers have built-in monitoring and configuration tools for storage, including RAID.

This chapter contains the following sections:

•Cisco Integrated Management Controller—Viewing Storage Properties, page 2-1

•Cisco UCS Server Configuration Utility—RAID Configuration, page 2-2

Note The tools and software referred to in this chapter are used only in C-series rack-mounted servers that are not integrated with Cisco UCS Manager.

Cisco Integrated Management Controller—Viewing Storage

Properties

CIMC is the management service for the C-Series servers and runs within the server.

You can use a web-based GUI or Secure Shell-based CLI to access, configure, administer, and monitor the server. Almost all tasks can be performed in either interface, and the results of tasks performed in one interface are displayed in another.

The configuration information for CIMC is located in the Cisco UCS C-Series Rack-Mount Servers Configuration Guide and the Cisco UCS C-Series Rack-Mount Servers CLI Configuration Guide. For details, see the guide that applies to the release that you are using.

A complete list of GUI and CLI configuration guides can be found here: Cisco UCS C-Series

Configuration Guides.

The following information is included:

•Storage adapters—Including all MegaRAID and Cisco Flexible Flash controllers.

•Controller information—that include the following:

–PCI information

–Manufacturing information

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Chapter 2 Using Cisco Integrated Management Controller and Cisco UCS Server Configuration Utility for RAID

Cisco Integrated Management Controller—Viewing Storage Properties

–Running and startup firmware image information

–Virtual and physical drive counts

–General settings

–Capabilities

–Hardware configuration

–Error counters

•Physical drive information—Including general drive information, identification information, and drive status.

•Virtual drive information—Including general drive information, RAID information, and physical drive information.

•Battery backup unit information (does not apply to Cisco Flexible Flash).

Cisco UCS Server Configuration Utility—RAID Configuration

You can use the RAID Configuration section in the Cisco UCS Server Configuration Utility document to configure your system RAID controllers.

RAID levels supported by SCU are RAID 0, 1, 5, and 6.

The latest documentation can be found here: Cisco UCS Server Configuration Utility, Release 3.0 User Guide.

If your system has multiple RAID controllers, Cisco UCS Server Configuration Utility displays a list of all available RAID devices. This feature is described in the Server Configuration section.

Three types of RAID configurations can be set up using Cisco UCS Server Configuration Utility. This feature is documented in the RAID configuration section.

•Automatic setup with redundancy

•Automatic setup without redundancy

•Create custom or multiple RAID arrays

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C H A P T E R 3

Using Cisco UCS Manager for RAID Configuring and Monitoring

This chapter describes monitoring and configuring your RAID controller using Cisco UCS Manager. The Cisco B-Series servers have built-in monitoring and configuration tools for storage, including RAID.

This chapter contains the following sections:

•Cisco UCS Manager Configuration, page 3-1

•Server Disk Drive Monitoring, page 3-7

•RAID Controllers in UCS Servers, page 3-10

Note Cisco UCS Manager is used both with B-series blade servers and C-series rack servers that have been integrated.

Cisco UCS Manager Configuration

Cisco UCS Manager interfaces with the LSI controllers and software and creates RAID configurations as part of creating local disk configuration policies, which allow the same configuration steps to be applied to many servers at once.

Local Disk Configuration Policy

This policy configures any optional SAS local drives that have been installed on a server through the onboard RAID controller of the local drive. This policy enables you to set a local disk mode for all servers that are associated with a service profile that includes the local disk configuration policy.

The local disk modes include the following:

•No Local Storage—For a diskless server or a SAN-only configuration. If you select this option, you cannot associate any service profile that uses this policy with a server that has a local disk.

•RAID 0 Striped—Data is striped across all disks in the array, providing fast throughput. There is no data redundancy, and all data is lost if any disk fails.

•RAID 1 Mirrored—Data is written to two disks, which provides complete data redundancy if one disk fails. The maximum array size is equal to the available space on the smaller of the two drives.

•Any Configuration—For a server configuration that carries forward the local disk configuration without any changes.

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Chapter 3 Using Cisco UCS Manager for RAID Configuring and Monitoring

Cisco UCS Manager Configuration

•No RAID—For a server configuration that removes the RAID and leaves the disk MBR and payload unaltered.

•RAID 5 Striped Parity—Data is striped across all disks in the array. Part of the capacity of each disk stores parity information that can be used to reconstruct data if a disk fails. RAID 5 provides good data throughput for applications with high read request rates.

•RAID 6 Striped Dual Parity—Data is striped across all disks in the array, and two parity disks are used to provide protection against the failure of up to two physical disks. In each row of data blocks, two sets of parity data are stored.

•RAID10 Mirrored and Striped— RAID 10 uses mirrored pairs of disks to provide complete data redundancy and high throughput rates.

You must include this policy in a service profile, and that service profile must be associated with a server for the policy to take effect.

Guidelines for all Local Disk Configuration Policies

Before you create a local disk configuration policy, consider the following guidelines:

•No Mixed HDDs and SSDs

Mixing HDD and SSDs in a single server or RAID configuration is not supported.

•Do Not Assign a Service Profile with the Default Local Disk Configuration Policy from a B200 M1 or M2 to a B200 M3

Due to the differences in the RAID/JBOD support provided by the storage controllers of B200 M1 and M2 servers and those of the B200 M3 server, you cannot assign or reassign a service profile that includes the default local disk configuration policy from a B200M1 or M2 server to a B200 M3 server. The default local disk configuration policy includes the Any Configuration or JBOD modes.

•Impact of Upgrade to Release 1.3(1i) or Higher

An upgrade from an earlier Cisco UCS firmware release to release 1.3(1i) or higher has the following impact on the Protect Configuration property of the local disk configuration policy the first time servers are associated with service profiles after the upgrade:

•Unassociated Servers

After you upgrade the Cisco UCS domain, the initial server association proceeds without configuration errors whether or not the local disk configuration policy matches the server hardware. Even if you enable the Protect Configuration property, Cisco UCS does not protect the user data on the server if there are configuration mismatches between the local disk configuration policy on the previous service profile and the policy in the new service profile.

Note If you enable the Protect Configuration property and the local disk configuration policy encounters mismatches between the previous service profile and the new service profile, all subsequent service profile associations with the server are blocked.

•Associated Servers

Any servers that are already associated with service profiles do not reboot after the upgrade. Cisco UCS Manager does not report any configuration errors if there is a mismatch between the local disk configuration policy and the server hardware.

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