Apple XSAN 1.4 Administrator Guide

0 (0)

Xsan

Administrator’s Guide for Xsan 1.4

K Apple Computer, Inc.

© 2006 Apple Computer, Inc. All rights reserved.

Under the copyright laws, this manual may not be copied, in whole or in part, without the written consent of Apple.

The Apple logo is a trademark of Apple Computer, Inc., registered in the U.S. and other countries. Use of the “keyboard” Apple logo (Option-Shift-K) for commercial purposes without the prior written consent of Apple may constitute trademark infringement and unfair competition in violation of federal and state laws.

Every effort has been made to ensure that the information in this manual is accurate. Apple is not responsible for printing or clerical errors.

Apple

1 Infinite Loop

Cupertino, CA 95014-2084 408-996-1010 www.apple.com

Apple, the Apple logo, Final Cut Pro, Mac, Macintosh, the Mac logo, Mac OS, Panther, Xsan, and Xserve are trademarks of Apple Computer, Inc., registered in the U.S. and other countries.

Finder and Tiger are trademarks of Apple Computer, Inc.

ADIC and StorNext are registered trademarks of Advanced Digital Information Corporation.

Intel and Intel Core are trademarks of Intel Corp. in the U.S. and other countries.

PowerPC and the PowerPC logo are trademarks of International Business Machines Corporation, under license therefrom.

Other company and product names mentioned herein are trademarks of their respective companies. Mention of third-party products is for informational purposes only and constitutes neither an endorsement nor a recommendation. Apple assumes no responsibility with regard to the performance or use of these products.

The product described in this manual incorporates copyright protection technology that is protected by method claims of certain U.S. patents and other intellectual property rights owned by Macrovision Corporation and other rights owners. Use of this copyright protection technology must be authorized by Macrovision Corporation and is intended for home and other limited viewing uses only unless otherwise authorized by Macrovision Corporation. Reverse engineering or disassembly is prohibited.

Apparatus Claims of U.S. Patent Nos. 4,631,603, 4,577,216, 4,819,098 and 4,907,093 licensed for limited viewing uses only.

Simultaneously published in the United States and Canada.

034-3767-A/07-21-06

Contents

11About This Book

12What’s New in Xsan 1.4

12 Version Compatibility

14 Upgrading from an Earlier Version of Xsan

14For More Information

15Notation Conventions

17 Chapter 1: Overview of Xsan

17 What Is Xsan?

19 Xsan Storage Area Networks

21 Shared SAN Volumes

21Controllers and Clients

22SAN Connections

23How Xsan Storage Is Organized

24LUNs

25Storage Pools

26Volumes

28 Folders with Affinities

28 How Xsan Utilizes Available Storage

3

28Metadata and Journal Data

29Striping at a Higher Level

30Security

30Expanding Storage

31Xsan Capacities

33Chapter 2: Setting Up a Storage Area Network

33Hardware and Software Requirements

34Supported Computers

34Supported Storage Devices

35Fibre Channel Fabric

36Ethernet TCP/IP Network

37Directory Services

38Outgoing Mail Service

39Planning Your SAN

41 Planning Considerations and Guidelines

50Connecting Computers and Storage Devices

51Preparing LUNs

51Using the Xsan Admin Application

52Installing Just the Xsan Admin Application

52 Connecting Through a Firewall

52 Xsan Admin Preferences

52Getting Help

53Using the Command Line

4Contents

53SAN and Volume Setup Summary

54Setting Up an Xsan Volume on a Storage Area Network

74Renaming a SAN

75Removing a SAN

75 Setting Up Additional SANs

77Chapter 3: Managing SAN Storage

78Adding Storage

79Restoring the Previous Volume Configuration After Changes

79About Rearranging Fibre Channel Connections

80Adding LUNs to a Storage Pool

82 Adding a Storage Pool to a Volume

84 Adding a Volume to a SAN

86Assigning a Storage Pool Affinity to a Folder

87Assigning an Affinity to a Folder Within a Folder

89Removing an Affinity

90Changing Storage Pool Settings

91Renaming a Storage Pool

92Choosing the Types of Files Stored on a Storage Pool

92 Setting Storage Pool Stripe Breadth

94Setting the Selection Method for Multiple Connections

95Changing Volume Settings

96Renaming a Volume

97Setting the Block Allocation Size

Contents

5

 

 

99Setting the Volume Allocation Strategy

100Enabling or Disabling Access Control Lists

101Choosing the Windows ID Mapping Method

101Checking Volume Fragmentation

102Defragmenting a Volume

103Checking the Integrity of a Volume

104Repairing a Volume

105Chapter 4: Managing Clients and Users

106Adding a Client

107Adding a Client to a StorNext SAN

108Mounting a Volume on a Client

109Controlling Client and User Access

109Controlling Access to Folders on Volumes

110Setting Up Access Control Lists

110 Unmounting a Volume on a Client

110Restricting a Client to Read-Only Access

111Removing a Client from a SAN

111Removing Xsan Software from a Computer

112Mapping Windows User and Group IDs

114Setting User and Group Quotas

115About Xsan Quotas

117 Checking User Quota Use

119 Helping Clients Check Their Own Quotas

6Contents

120Creating Local Home Folders for Network Accounts

121Chapter 5: Managing Metadata Controllers

122Adding a Controller

123Setting Controller Failover Priority

124Switching to a Standby Controller

125Finding Out Which Controller Is Hosting a Volume

127Listing the Volumes Hosted by a Controller

128Changing a Controller’s IP Address

129Upgrading Controller Software

130Monitoring Controller Status

131Chapter 6: Monitoring SAN Status

132Locking Xsan Admin Views for Secure Monitoring

133Checking Overall SAN Status

134Checking Overall Volume Status

135Checking Free Space on a Volume

136Checking Free Space on a Storage Pool

136 Checking Quota Use

136Viewing a Controller’s CPU and Network Utilization

137Viewing File System CPU and Memory Utilization

138Setting Up Status Notifications

139Checking the Status of File System Processes

139 Viewing Xsan Logs

Contents

7

 

 

140Checking Volume Clients

141Checking for Fibre Channel Connection Failures

141 Checking the State of Xserve RAID Systems

143 Chapter 7: Solving SAN Problems

143 A Dialog on a Client Reports That a LUN Is Unreadable

143You’re Unable to Connect to a Computer Using Xsan Admin

144You’re Unable to Install the Xsan Software

144 Some Computers Aren’t Listed in Xsan Admin

144You’re Unable to Mount a Volume on a Client

145Xserve RAID LUNs Aren’t Accessible over Fibre Channel

145You’re Unable to Restart a Volume After Adding LUNs or Storage Pools

146Some LUNs Aren’t Listed in Xsan Admin

147Some LUNs Are Listed Twice in Xsan Admin

147Files and Folders Created by Mac OS 9 Computers Show the Wrong Creation Date

148Problems Using Command-Line Tools

148A LUN Doesn’t Have as Much Space as Expected

149You’re Unable to Rename an Xsan Volume in the Finder

149

Fibre Channel Performance Is Poorer Than Expected

149

A Client User Sees Error Code –1425

149

File Copy Doesn’t Finish

150

A Client is Unable to Use a Volume After a Fibre Channel Interruption

150

SAN Performance Declines Periodically and Predictably

151

You’re Unable to Add a Storage Pool

8Contents

152You’re Unable to Add LUNs to a Storage Pool

153The Capacity of a Larger LUN is Listed as 2 Terabytes

155Appendix A: Combining Xsan and StorNext Clients and Controllers

155Terminology

156Compatible Software Versions

156Licensing

157Adding Macintosh Clients to a StorNext SAN

159 Using Xsan Controllers with StorNext Clients

161Appendix B: Using the Command Line

161Using the Shell Commands

162Sending Commands to Remote Computers

162Viewing the Man Pages

163Notation Conventions

164The Commands

164 Viewing or Changing Volume and Storage Pool Settings (cvadmin)

168 Copying Files or Folders (cvcp)

171Checking or Repairing a Volume (cvfsck)

172Labeling, Listing, and Unlabeling LUNs (cvlabel)

173Creating a Folder with an Affinity (cvmkdir)

174Creating and Preallocating a File (cvmkfile)

175Initializing a Volume (cvmkfs)

176Applying Volume Configuration Changes (cvupdatefs)

Contents

9

 

 

176Starting a Volume Controller (fsm)

177Starting a Port Mapper Process (fsmpm)

177 Defragmenting a File, Folder, or Volume (snfsdefrag)

179Mounting an Xsan Volume

180Unmounting an Xsan Volume

181Viewing Logs

181 The Configuration Files

181 Examples

183 Glossary

187 Index

10 Contents

About This Book

Preface

Use this guide to learn how to set up and manage Xsan volumes on a storage area network.

This guide shows how to use Xsan to combine Xserve RAID arrays and slices into large, easy-to-expand volumes of storage that clients use like local disks but are actually shared over a high-speed Fibre Channel fabric.

Chapter 1 provides an overview of Xsan and how you can use it to organize RAID arrays into shared volumes of storage.

Chapter 2 includes hardware and software requirements, SAN planning guidelines, and basic steps for setting up an Xsan volume.

Chapter 3 contains instructions for expanding storage, creating folders with affinities, changing volume and storage pool settings, and checking, defragmenting, and repairing SAN volumes.

Chapter 4 shows how to add client computers to a SAN, mount volumes on clients, control client and user access to SAN files, and control user space using quotas.

Chapter 5 contains information about managing volume metadata controllers.

Chapter 6 includes instructions for monitoring and automatically reporting the condition of a SAN.

11

Chapter 7 lists solutions to common problems you might encounter.

Appendix A contains information to help you combine Xsan controllers or clients with ADIC StorNext controllers or clients on the same SAN.

Appendix B describes command-line utilities and configuration files you can use to manage an Xsan SAN using Terminal.

What’s New in Xsan 1.4

Xsan 1.4 offers these new features and capabilities:

ÂYou can use access control lists (ACLs) to manage user access to Xsan volumes.

ÂXsan runs on Intel-based Macintosh computers.

Version Compatibility

The following table shows which versions of Xsan and StorNext controllers and clients can be used on the same SAN.

Important: If you set up a LUN that is larger than 2 terabytes (TB), be aware that older clients (those running Xsan on Mac OS X 10.3 Panther or Xsan 1.2 or earlier on

Mac OS X 10.4 Tiger) cannot read these large LUNs. A dialog appears on these older clients that says the LUN is unreadable. Be sure to click Ignore to dismiss this dialog. Do not click Format, or information on the corresponding Xsan volume will be lost. If you use LUNs greater than 2 TB, you should upgrade all SAN clients to Xsan 1.3 or later on Mac OS X or Mac OS X Server v10.4.

12 Preface About This Book

Controller

Client

Compatible

Xsan 1.4

Xsan 1.4

Yes

 

 

 

 

Xsan 1.3 (Mac OS X v10.4)

Yes

 

 

 

 

Xsan 1.3 (Mac OS X v10.3)

Yes, for LUNs < 2 TB

 

 

 

 

Xsan 1.2 or earlier

No

 

 

 

 

StorNext 2.8

No

 

 

 

 

StorNext FX 1.3 or 1.4

Yes

 

 

 

 

StorNext 2.6 or 2.7

Yes

 

 

 

 

StorNext 2.5 or earlier

No

 

 

 

Xsan 1.3 (Mac OS X v10.4)

Xsan 1.4

No

 

 

 

 

Xsan 1.3 (Mac OS X v10.4)

Yes

 

 

 

 

Xsan 1.3 (Mac OS X v10.3)

Yes

 

 

 

 

StorNext FX 1.3 or 1.4

Yes

 

 

 

 

StorNext 2.6 or 2.7

Yes

 

 

 

 

StorNext 2.5 or earlier

No

 

 

 

StorNext 2.8

Xsan 1.4 or 1.3

Yes

 

 

 

StorNext 2.7

Xsan 1.4 or 1.3

Yes

 

 

 

StorNext 2.6 or earlier

Xsan 1.4 or 1.3

No

 

 

 

Preface About This Book

13

 

 

Upgrading from an Earlier Version of Xsan

For more information about migrating your SAN storage to Xsan 1.4 from an earlier version of Xsan, including tips for upgrading with the least impact on existing storage, see the Xsan Migration Guide at www.apple.com/server/documentation/.

For More Information

For more information about Xsan, consult these resources:

Read Me documents—important updates and special information. Look for them on the Xsan installation disc.

Xsan website (www.apple.com/xsan/)—gateway to extensive product and technology information.

Xsan Support website (www.apple.com/support/xsan/)—access to articles about Xsan from Apple’s support organization.

Apple customer training (train.apple.com/)—instructor-led and self-paced courses for honing your Xsan administration skills.

Apple discussion groups (discussions.info.apple.com/)—a way to share questions, knowledge, and advice with other Xsan administrators.

Apple mailing list directory (www.lists.apple.com/)—subscribe to mailing lists so you can communicate with other Xsan administrators using email.

14 Preface About This Book

Notation Conventions

The following conventions are used in this book wherever shell commands or other command-line items are described.

Notation

Indicates

fixed-width font

A command or other terminal text

 

 

$

A shell prompt

 

 

[text_in_brackets]

An optional parameter

 

 

(one|other)

Alternative parameters (type one or the other)

 

 

underlined

A parameter you must replace with a value

 

 

[...]

A parameter that may be repeated

 

 

<angle_brackets>

A displayed value that depends on your SAN configuration

 

 

Preface About This Book

15

 

 

1

Overview of Xsan

1

 

 

 

 

This chapter gives you an overview of Xsan and storage area networks.

Read this chapter for an overview of Xsan and how you can use it to set up a storage area network (SAN) to provide fast, shared storage.

What Is Xsan?

Xsan is a storage area network file system and a management application (Xsan Admin) that you can use to provide users or applications on client computers with shared high-speed access to expandable storage.

17

Mac OS X

San Volume

Xsan lets you

 

combine RAID arrays

File data moves

into volumes clients

over Fibre Channel

use like local disks.

 

Storage

pools

RAID arrays (LUNs)

18 Chapter 1 Overview of Xsan

Xsan Storage Area Networks

A storage area network is a way of connecting computers to storage devices that gives users very fast access to files and gives administrators the ability to expand storage capacity as needed without interrupting users.

An Xsan SAN consists of:

ÂVolumes of shared storage, stored on Xserve RAID systems, available to clients as mounted volumes that they can use like local disks

ÂAt least one computer acting as a metadata controller that coordinates access to the shared volumes

ÂClient computers that access storage in accordance with established permissions and quotas

ÂUnderlying Fibre Channel and Ethernet networks

The following illustration shows the physical components of a typical Xsan SAN.

Chapter 1 Overview of Xsan

19

 

 

Apple XSAN 1.4 Administrator Guide

Clients

Ethernet - TCP/IP (Public)

Ethernet - TCP/IP (Private)

Metadata controller

Standby controller

Fibre

Channel switch

Xserve RAID storage

Intranet/

Internet

20 Chapter 1 Overview of Xsan

Shared SAN Volumes

Users and applications see shared SAN storage as local volumes. Xsan volumes are logical disks made up of groups of RAID arrays. The elements you combine to create an Xsan volume are described under “How Xsan Storage Is Organized” on page 23.

Controllers and Clients

When you add a computer to an Xsan SAN, you specify whether it will play the role of client, controller, or both.

Controllers

When you set up an Xsan SAN, you assign at least one computer to act as the controller. The controller manages the SAN volume metadata, maintains a file system journal, and controls concurrent access to files. Metadata includes such information as where files are actually stored and what portions of available storage are allocated to new files.

For high availability, you should add more than one controller to a SAN, as shown in the illustration on page 20. If the primary controller fails, the standby controller takes over. Though not recommended for best performance, controllers can also act as clients, so you can use a standby controller as a working client while the primary controller is operational.

Clients

The computers that users or applications use to access SAN volumes are called clients. Clients communicate with controllers over the Ethernet network but use Fibre Channel to send and retrieve file data to and from the RAID systems that provide storage for the volumes.

Chapter 1 Overview of Xsan

21

 

 

SAN Connections

Xsan uses independent networks to connect storage devices, metadata controllers, and client computers: a Fibre Channel network and one or two Ethernet networks.

User Data Over Fibre Channel

User data is transferred over high-speed Fibre Channel connections. Controllers also use a Fibre Channel connection to move metadata to and from the volume.

Metadata Over Ethernet

To eliminate unnecessary traffic on the Fibre Channel connections, controllers and clients use an Ethernet network to exchange file system metadata. (When a controller reads or writes metadata on a volume, it uses Fibre Channel.) The Xsan Admin application also uses the Ethernet connection to let you manage the SAN.

To prevent Internet or intranet traffic from interfering with metadata communications, you should set up separate Ethernet networks as shown in the illustration on page 20.

Fibre Channel Multipathing

Xsan can take advantage of multiple Fibre Channel connections between clients and storage. Xsan can alternate between connections for each read and write, or assign each LUN in a volume to one of the connections when the volume is mounted.

22 Chapter 1 Overview of Xsan

How Xsan Storage Is Organized

Users use an Xsan volume the same way they use a local disk. What they don’t see is that the SAN volume actually consists of numerous physical disks combined on several levels using RAID techniques.

The following illustration shows an example of how disk space provided by the individual drive modules in several Xserve RAID systems is combined into a volume that users see as a large local disk.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Faster

 

 

 

 

 

 

Shared

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SAN volume

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Affinity

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Safer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Affinity

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Storage pool

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Storage pool

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Striping)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Striping)

 

 

 

 

 

 

 

 

 

 

 

 

 

LUN

 

 

 

 

LUN

 

 

 

LUN

 

 

 

LUN

 

 

LUN

 

 

 

 

LUN

 

 

 

LUN

 

 

 

LUN

 

RAID 0

 

 

RAID 0

 

RAID 0

 

RAID 0

RAID 5

 

 

RAID 5

 

RAID 5

 

RAID 5

 

 

array

 

 

 

array

 

 

array

 

 

array

 

array

 

 

 

array

 

 

array

 

 

array

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Chapter 1 Overview of Xsan

23

 

 

The following paragraphs describe these storage elements and how you organize them to create shared Xsan volumes.

LUNs

The smallest storage element you work with in Xsan is a logical storage device called a LUN (a SCSI logical unit number). In most storage area networks a LUN represents a group of drives such as a RAID array or a JBOD (just a bunch of disks) device. In Xsan, LUNs are Xserve RAID arrays or slices.

You create a LUN when you use the RAID Admin application to create an Xserve RAID array. The controller hardware and software in the Xserve RAID system combine individual drive modules into an array based on the RAID scheme you choose. Each array appears on the network as a separate LUN. If you slice an array, each slice appears as a LUN.

One of your first tasks when you set up a SAN volume is to prepare LUNs. If the two RAID 5 arrays on a new Xserve RAID are not right for your application, you can use RAID Admin to create arrays based on other RAID schemes. For help choosing schemes for your LUNs, see “Choosing RAID Schemes for LUNs” on page 44.

The illustration on page 23 shows four Xserve RAID systems that each host two arrays. Half of the arrays use a RAID 0 scheme (striping only) for speed while the others use RAID 5 (distributed parity) to ensure against data loss. Xsan sees the arrays as LUNs that can be combined to create a volume.

After your Xserve RAID LUNs are set up, you label and initialize them for use with the Xsan file system using Xsan Admin.

24 Chapter 1 Overview of Xsan

Storage Pools

LUNs are combined to form storage pools. A storage pool in a small volume might consist of a single RAID array, but storage pools in many volumes consist of multiple arrays.

Xsan distributes file data in parallel across the LUNs in a storage pool using a RAID 0 (striping) scheme. So, you can improve a client’s access speed by distributing available storage over several LUNs in a storage pool.

You can set up storage pools that have different performance or recoverability characteristics and assign folders to them using affinities. Users can then select where to store files based on their need for speed or safety. See “Folders with Affinities” on page 28.

The illustration on page 23 shows eight LUNs combined into two storage pools, one pool consisting of RAID 0 (fast, but not recoverable) arrays and the other made up of RAID 5 (not as fast, but recoverable) arrays. Xsan stripes data across the four LUNs in each storage pool.

You use Xsan Admin to add available LUNs to specific storage pools.

Chapter 1 Overview of Xsan

25

 

 

Volumes

Storage pools are combined to create the volumes that users see. From the user’s perspective, the SAN volume looks and behaves just like a large local disk, except that:

ÂThe size of the volume can grow as you add underlying arrays or storage pools

ÂOther users on the SAN can access files on the volume at the same time

In the illustration on page 23, two storage pools are combined to create a single shared volume.

You create volumes and mount them on client computers using the Xsan Admin application.

26 Chapter 1 Overview of Xsan

The following screen image shows how LUNs, storage pools, and volumes appear as you organize them in Xsan Admin. This example shows a SAN named “Editing SAN” with a single shared volume named “SanVol.” Storage for the volume is provided by two storage pools,“Meta” and “Data,” the first based on a single LUN and the second on two. Each of the LUNs is a 3-disk RAID 5 array on an Xserve RAID using 115 GB drive modules.

SAN

Volume

LUN

Storage pool

Chapter 1 Overview of Xsan

27

 

 

Folders with Affinities

To control which storage pool is used to store specific files (for example, to provide different levels of service for different users or applications), you can associate a folder on an Xsan volume with one of the storage pools that make up the volume.

If, for example, you set up storage pools with different balances of performance and data redundancy, users can choose between faster and safer storage by putting files in the appropriate folder.

In the illustration on page 23, a predefined folder has an affinity for the faster storage pool that is based on RAID 0 arrays. Any file that a user copies into this folder is automatically stored on the faster arrays. A second folder is associated with the more secure RAID 5 storage.

How Xsan Utilizes Available Storage

Xsan stores both user files and file system data on SAN volumes, and stripes data across the LUNs in a volume for better performance.

Metadata and Journal Data

Xsan records information about the files in an Xsan volume using metadata files and file system journals. File system metadata includes information such as which specific parts of which disks are used to store a particular file and whether the file is being accessed. The journal data includes a record of file system transactions that can help ensure the integrity of files in the event of a failure.

28 Chapter 1 Overview of Xsan

These files are managed by the Xsan metadata controller, but are stored on SAN volumes, not on the controller itself. By default, metadata and journal data are stored on the first storage pool you add to a volume. You can use Xsan Admin to choose where these files are stored when you add storage pools to a new volume.

Striping at a Higher Level

When you write a file to a RAID array using RAID 0 (striping), the file is broken into segments that are spread across the individual disk drives in the array. This improves performance by writing pieces of the file in parallel (instead of one piece at a time) to the individual disks in the array. Xsan applies this same technique at a second, higher level in the storage hierarchy. Within each storage pool in a volume, Xsan stripes file data across the individual LUNs that make up the storage pool. Once again, performance is improved because data is written in parallel.

You can tune SAN performance by adjusting the amount of data written to each LUN in a storage pool (the “stripe breadth”) to suit a critical application.

Chapter 1 Overview of Xsan

29

 

 

Security

As the SAN administrator, you can control access to shared volumes in several ways.

First, users cannot browse or mount SAN volumes. Only a SAN administrator can specify which volumes are mounted on which client computers. One way you can control access to data is to mount a volume only on appropriate client computers.

To prevent users from modifying data on a volume, you can mount the volume with read-only access.

You can control user access to folders on a volume by setting up access control lists (ACLs) in Workgroup Manager or by specifying owner, group, and general access permissions in the Finder.

You can also set up zones in the underlying Fibre Channel network to segregate users and volumes.

Expanding Storage

There are two ways you can add free space to an Xsan volume:

ÂAdd Xserve RAID systems (new LUNs) to existing storage pools

ÂAdd entire new storage pools to volumes

Both methods require you to unmount and remount the volume on clients.

You can also add new volumes to a SAN at any time.

For information about expanding Xsan storage, see “Adding Storage” on page 78.

30 Chapter 1 Overview of Xsan

Loading...
+ 162 hidden pages