Pages - fc, bc, 8, 17, 23-24 & 43: Applied new logo, applied new page numbering convention, deleted Index [no
Rev. B01/29/2015
Rev. C02-09-2015 Pages 11 & 16-17: Corrected AFR value to 0.44%
Rev. D07-06-2015
Rev. E04-11-2016
longer needed], removed “Canadian Department of Communications”, changed MTBF to 2M, changed to "Maximum
Rated Workload" & updated Workload text, delete text in Section 5.2.1, updated DC power tables & added Sanitize
(Overwrite) command.
Page FC: Applied new cover design/layout.
Pages FC, 7, 10, 12-13, 27, 38, 44-45 & 47-48: Added 512N models & specs, added models to Inquiry Data
Pages 47-48: Mode Sense Data - page 83 edits
13: Revised 5xxN Areal, Track and Peak Bit Densities
17: Revised Warranty link text to - “Is my Drive under Warranty”
21: Revised Storage statement
SeaTools are either trademarks or registered trademarks of Seagate Technology LLC or one of its affiliated companies in the United States and/or other countries. The FIPS logo is a certification mark of NIST, which does not imply product endorsement by NIST, the U.S., or Canadian governments. All other trademarks or registered trademarks are the property of their
respective owners.
No part of this publication may be reproduced in any form without written permission of Seagate Technology LLC.
Call 877-PUB-TEK1 (877-782-8351) to request permission.
When referring to drive capacity, one gigabyte, or GB, equals one billion bytes and one terabyte, or TB, equals one trillion bytes. Your computer’s operating system may use a different
standard of measurement and report a lower capacity. In addition, some of the listed capacity is used for formatting and other functions, and thus will not be available for data storage.
Actual quantities will vary based on various factors, including file size, file format, features and application software. Actual data rates may vary depending on operating environment
and other factors. The export or re-export of hardware or software containing encryption may be regulated by the U.S. Department of Commerce, Bureau of Industry and Security (for
more information, visit www.bis.doc.gov), and controlled for import and use outside of the U.S. Seagate reser ves the right to change, without notice, product offerings or specifications.
For information regarding online support and services, visit: http://www.seagate.com/contacts/
For information regarding Warranty Support, visit: http://www.seagate.com/support/warranty-and-replacements/
For information regarding data recovery services, visit: http://www.seagate.com/services-software/seagate-recovery-
services/recover/
For Seagate OEM, Distribution partner and reseller portals, visit: http://www.seagate.com/partners
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 6
1.0Scope
This manual describes Seagate® Enterprise Capacity 2.5 HDD v3 SAS (Serial Attached SCSI) disk drives.
Enterprise Capacity 2.5 HDD v3 drives support the SAS Protocol specifications to the extent described in this manual. The SAS Interface Manual (part
number 100293071) describes the general SAS characteristics of this and other Seagate SAS drives. The Self-Encrypting Drive Reference Manual,
part number 100515636, describes the interface, general operation, and security features available on Self-Encrypting Drive models.
Product data communicated in this manual is specific only to the model numbers listed in this manual. The data listed in this manual may not be
predictive of future generation specifications or requirements. If integrators are designing a system which will use one of the models listed or future
generation products and need further assistance, please contact the Field Applications Engineer (FAE) or our global support services group as
shown on page 6.
Unless otherwise stated, the information in this manual applies to standard and Self-Encrypting Drive models.
Note
Note
Note
Sector
Size
Standard
models
Self-Encrypting Drive
(SED) models
FIPS 140-2 Level 2
(SED-FIPS) models
ST2000NX0263ST2000NX0323ST2000NX0333
4096N
ST1000NX0323ST1000NX0363
ST2000NX0273ST2000NX0343ST2000NX0353
512E
ST1000NX0333ST1000NX0373
ST2000NX0433
512N
ST1000NX0453
Throughout this manual, 512E represents 512 “emulation” sector drives, 512N
represents 512 “native” sector drives and 4096N represents 4096 “native”
sector drives.
Previous generations of Seagate Self-Encrypting Drive models were called Full
Disk Encryption (FDE) models before a differentiation between drive-based
encryption and other forms of encryption was necessary
The Self-Encrypting Drive models indicated on the cover of this product manual have
provisions for “Security of Data at Rest” based on the standards defined by the
Trusted Computing Group (see www.trustedcomputin
ggroup.org).
For more information on FIPS 140-2 Level 2 certification see Section 7.0 on page 32.
For product certification status visit - http://csrc.nist.gov/groups/STM/cmvp/documents/140-1/1401vend.htm.
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 7
2.0Applicable standards and reference documentation
The drives documented in this manual have been developed as system peripherals to the highest standards of design and construction. The drives
depend on host equipment to provide adequate power and environment for optimum performance and compliance with applicable industry and
governmental regulations. Special attention must be given in the areas of safety, power distribution, shielding, audible noise control, and
temperature regulation. In particular, the drives must be securely mounted to guarantee the specified performance characteristics. Mounting by
bottom holes must meet the requirements of Section 10.3.
2.1Standards
The Enterprise Capacity 2.5 HDD v3 family complies with Seagate standards as noted in the appropriate sections of this manual and the Seagate SAS
Interface Manual, part number 100293071.
The drives are recognized in accordance with UL 60950-1, CSA 60950-1, and EN60950-1.
The security features of Self-Encrypting Drive models are based on the “TCG Storage Architecture Core Specification” and the “TCG Storage
Workgroup Security Subsystem Class: Enterprise_A” specification with additional vendor-unique features as noted in this product manual.
2.1.1Electromagnetic compatibility
The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to use. The drive is supplied as a
subassembly and is not subject to Subpart B of Part 15 of the FCC Rules and Regulations.
The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides reasonable shielding. The drive is
capable of meeting the Class B limits of the FCC Rules and Regulations when properly packaged; however, it is the user’s responsibility to assure that
the drive meets the appropriate EMI requirements in their system. Shielded I/O cables may be required if the enclosure does not provide adequate
shielding. If the I/O cables are external to the enclosure, shielded cables should be used, with the shields grounded to the enclosure and to the host
controller.
2.1.1.1Electromagnetic susceptibility
As a component assembly, the drive susceptibility drive was tested in a representative system for typical applications. It is the responsibility of those
integrating the drive within their systems to perform those tests required and design their system to ensure that equipment operating in the same
system as the drive or external to the system does not adversely affect the performance of the drive. See Section 6.3, DC power requirements.
2.1.2Electromagnetic compliance
Seagate uses an independent laboratory to confirm compliance with the directives/standards for CE Marking and RCM Marking. The drive was
tested in a representative system for typical applications and comply with the Electromagnetic Interference/Electromagnetic Susceptibility (EMI/
EMS) for Class B products.
Although the test system with this Seagate model complies with the directives/standards, we cannot guarantee that all systems will comply. The
computer manufacturer or system integrator shall confirm EMC compliance and provide the appropriate marking for their product.
Electromagnetic compliance for the European Union
If this model has the CE Marking it complies with the European Union requirements of the Electromagnetic Compatibility Directive 2004/108/EC as
put into place on 20 July 2007.
Canada ICES-003
If this model has the ICES-003 Marking it complies with the Canadian Standard Association Standard CAN/CSA-CISPR 22-10, Information
Technology Equipment - Radio Disturbance Characteristics - Limits and Methods of Measurement.
Australian RCM Mark
If this model has the RCM Marking it complies with the Australia/New Zealand Standard AS/NZ CISPR22 and meets the Electromagnetic
Compatibility (EMC) Framework requirements of Australia’s Radiocommunications Act.
Korean KCC
If these drives have the Korean Communications Commission (KCC) logo, they comply with KN22, KN 24, and KN61000.
Taiwanese BSMI
If this model has the Taiwanese certification mark then it complies with Chinese National Standard, CNS13438.
2.1.3European Union Restriction of Hazardous Substances (RoHS)
The European Union Restriction of Hazardous Substances (RoHS) Directive restricts the presence of chemical substances, including Lead (Pb), in
electronic products effective July 2006.
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 8
A number of parts and materials in Seagate products are procured from external suppliers. We rely on the representations of our suppliers
regarding the presence of RoHS substances in these parts and materials. Our supplier contracts require compliance with our chemical substance
restrictions, and our suppliers document their compliance with our requirements by providing material content declarations for all parts and
materials for the disk drives documented in this publication. Current supplier declarations include disclosure of the inclusion of any RoHS-regulated
substance in such parts or materials.
Seagate also has internal systems in place to ensure ongoing compliance with the RoHS Directive and all laws and regulations which restrict
chemical content in electronic products. These systems include standard operating procedures that ensure that restricted substances are not
utilized in our manufacturing operations, laboratory analytical validation testing, and an internal auditing process to ensure that all standard
operating procedures are complied with.
2.1.4China Restriction of Hazardous Substances (RoHS) Directive
This product has an Environmental Protection Use Period (EPUP) of 20 years. The following table contains information mandated by
China's "Marking Requirements for Control of Pollution Caused by Electronic Information Products" Standard.
"O" indicates the hazardous and toxic substance content of the part (at the homogeneous material level) is lower than the threshold defined by the
China RoHS MCV Standard.
"X" indicates the hazardous and toxic substance content of the part (at the homogeneous material level) is over the threshold defined by the China
RoHS MCV Standard.
2.2Reference documents
SAS Interface ManualSeagate part number: 100293071
SCSI Commands Reference ManualSeagate part number: 100293068
Self-Encrypting Drives Reference Manual
ANSI SAS DocumentsSFF-8223 2.5” Drive Form Factor with Serial Connector
ANSI Small Computer System Interface (SCSI) Documents
Trusted Computing Group (TCG) Documents (apply to Self-Encrypting Drive models only)
In case of conflict between this document and any referenced document, this document takes precedence.
Seagate part number: 100515636
SFF-8460 HSS Backplane Design Guidelines
SFF-8470 Multi Lane Copper Connector
SFF-8482 SAS Plug Connector
ANSI INCITS.xxx Serial Attached SCSI (SAS-2) Standard (T10/1562-D)
ISO/IEC 14776-xxx SCSI Architecture Model-3 (SAM-4) Standard (T10/1561-D)
ISO/IEC 14776-xxx SCSI Primary Commands-3 (SPC-4) Standard (T10/1416-D)
ISO/IEC 14776-xxx SCSI Block Commands-2 (SBC-3) Standard (T10/1417-D)
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 9
3.0General description
Enterprise Capacity 2.5 HDD v3 SAS drives provide high performance, high capacity data storage for a variety of systems including engineering
workstations, network servers, mainframes, and supercomputers. The Serial Attached SCSI interface is designed to meet next-generation
computing demands for performance, scalability, flexibility and high-density storage requirements.
Enterprise Capacity 2.5 HDD v3 drives are random access storage devices designed to support the Serial Attached SCSI Protocol as described in the
ANSI specifications, this document, and the SAS Interface Manual (part number 100293071) which describes the general interface characteristics of
this drive. Enterprise Capacity 2.5 HDD v3 drives are classified as intelligent peripherals and provide level 2 conformance (highest level) with the
ANSI SCSI-1 standard. The SAS connectors, cables and electrical interface are compatible with Serial ATA (SATA), giving future users the choice of
populating their systems with either SAS or SATA hard disk drives. This allows integrators to continue to leverage existing investment in SCSI while
gaining a 12Gb/s serial data transfer rate.
The Self-Encrypting Drive models indicated on the cover of this product manual have provisions for “Security of Data at Rest” based on the
standards defined by the Trusted Computing Group (see www.trustedcomputinggroup.or
The head and disk assembly (HDA) is sealed at the factory. Air recirculates within the HDA through a non-replaceable filter to maintain a
contamination-free HDA environment.
g).
Note
Enterprise Capacity 2.5 HDD v3 drives use a dedicated load/unload zone at the outermost radius of the media to eliminate the possibility of
destroying or degrading data by landing in the data zone. The heads automatically go to the ramp load/unload when power is removed from the
drive and during the deeper sleep modes.
An automatic shipping lock prevents potential damage to the heads and discs that results from movement during shipping and handling. The
shipping lock disengages and the head load process begins when power is applied to the drive.
These drives decode track 0 location data from the servo data embedded on each surface to eliminate mechanical transducer adjustments and
related reliability concerns.
The drives also use a high-performance actuator assembly with a low-inertia, balanced, patented, straight arm design that provides excellent
performance with minimal power dissipation.
Never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads, media, actuator, etc.) as this
requires special facilities. The drive does not contain user-replaceable parts. Opening the HDA for any reason voids the warranty.
3.1Standard features
Enterprise Capacity 2.5 HDD drives have the following standard features:
•Dedicated head load/unload zone and automatic shipping lock
•Drive Self Test (DST)
•Dynamic spindle brake
•ECC maximum burst correction length of 524 bits for 512 byte blocks and 4108 bits for 4k byte blocks
•Embedded servo design
•Firmware downloadable using the SAS interface
•Flawed logical block reallocation at format time
•Idle Read After Write (IRAW)
•Industry standard SFF 2.5-inch dimensions
•Integrated dual port SAS controller supporting the SCSI protocol
•Jumperless configuration
•No preventive maintenance or adjustments required
•NVC- backed write cache of approximately 334K
•Power Choice
•Power Save
•Programmable auto write and read reallocation
•Programmable logical block reallocation scheme
•RAID Rebuild™
•Reallocation of defects on command (Post Format)
•SAS Power Disable
•Self diagnostics performed when power is applied to the drive
•Support for SAS expanders and fanout adapters
•Supports up to 16 initiators
•User-selectable logical block sizes for 4096N models (4096, 4160, 4192 or 4224 bytes per logical block)
•User-selectable logical block sizes for 512E and 512N models (512, 520, 524 or 528 bytes per logical block)
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 10
•Vertical, horizontal, or top down mounting
•Zone bit recording (ZBR)
Self-Encrypting Drive models have the following additional features:
•16 independent data bands
•Authenticated firmware download
•Automatic data encryption/decryption
•Controlled access
•Cryptographic erase of user data for a drive that will be repurposed or scrapped
•Drive locking
•Random number generator
3.2Media description
The media used on the drive has an glass substrate coated with a thin film magnetic material, overcoated with a proprietary protective layer for
improved durability and environmental protection.
•Firmware-controlled multisegmented cache designed to dynamically adjust segments for enhanced system performance
•Supports start and stop commands (spindle stops spinning)
Note
There is no significant performance difference between Self-Encrypting Drive and standard (non-Self-Encrypting Drive) models.
3.4Reliability
•5-year warranty
•Annualized Failure Rate (AFR) of 0.44%
•Balanced low mass rotary voice coil actuator
•Incorporates industry-standard Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.)
•Mean Time Between Failures (MTBF) of 2,000,000 hours
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 11
3.5Formatted capacities
Standard OEM models are formatted to 512 bytes per block for 512E (emulation) and 512N (native) drives and 4096 bytes per block for 4096N
(native) drives. The block size is selectable at format time. Supported block sizes are 512, 520, 524, and 528 for 512E and 512N drives and 4096, 4160,
4192, and 4224 for 4096N drives. Users having the necessary equipment may modify the data block size before issuing a format command and
obtain different formatted capacities than those listed.
To provide a stable target capacity environment and at the same time provide users with flexibility if they choose, Seagate recommends product
planning in one of two modes:
Seagate designs specify capacity points at certain block sizes that Seagate guarantees current and future products will meet. We recommend
customers use this capacity in their project planning, as it ensures a stable operating point with backward and forward compatibility from
generation to generation. The current guaranteed operating points for this product are:
Capacity (Blocks)
2TB1TB
Sector Size
DecimalHexDecimalHex
512
520
524
528
4096
4160
4192
4224
3,907,029,168E8E088B0
3,824,358,992E3F31650
3,773,385,336E0E94A781,882,972,568703BE198
3,719,165,192DDADF508
488,378,6461D1C1116
478,846,1601C8A9CD0
472,805,3441C2E6FE0236,402,672E1737F0
469,223,4881BF7C840
1,953,525,16874706DB0
1,923,076,936729FD348
1,876,331,3366FD68B48
244,190,646E8E0DB6
239,423,080E454E68
234,611,744DFBE420
3.6Programmable drive capacity
Using the Mode Select command, the drive can change its capacity to something less than maximum. See the Mode Select (6) parameter list table
in the SAS Interface Manual, part number 100293071. A value of zero in the Number of Blocks field indicates that the drive will not change the
capacity it is currently formatted to have. A number other than zero and less than the maximum number of LBAs in the Number of Blocks field
changes the total drive capacity to the value in the Number of Blocks field. A value greater than the maximum number of LBAs is rounded down to
the maximum capacity.
3.7Factory-installed options
The following items may be ordered which are incorporated at the manufacturing facility during production or packaged before shipping. Some of
the options available are (not an exhaustive list of possible options):
•Other capacities can be ordered depending on sparing scheme and sector size requested.
•Single-unit shipping pack. The drive is normally shipped in bulk packaging to provide maximum protection against transit damage. Units
shipped individually require additional protection as provided by the single unit shipping pack. Users planning single unit distribution should
specify this option.
•The Safety and Regulatory Agency Specifications, part number 75789512, is usually included with each standard OEM drive shipped, but extra
copies may be ordered.
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 12
4.0Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of Enterprise Capacity 2.5 HDD v3 drives.
Drive capacity2000200010001000GB (formatted, rounded off value)
Read/write data heads101055
Bytes per track979979979979KBytes (avg, rounded off values)
Bytes per surface200,000200,000200,000200,000MB (unformatted, rounded off value)
Tracks per surface (total)197197197197Ktracks (user accessible, rounded off values)
(4096N, 512E or 512N)
Tracks per inch315335315335KTPI (average) (4096N, 512E or 512N)
Peak bits per inch1889199818891998KBPI
Areal density585640585640Gb/in2 (4096N, 512E or 512N)
Disk rotation speed7.2K7.2K7.2K7.2Krpm
Avg rotational latency4.1674.1674.1674.167ms
4.2Performance characteristics
4.2.1Format command execution time for 512-byte sectors (minutes)
2TB models1TB models
Maximum (with certify)
Maximum (without certify)
Execution time measured from receipt of the last byte of the Command Descriptor Block (CDB) to the request for a Status Byte Transfer to the
Initiator (excluding connect/disconnect).
When changing sector sizes, the format times shown above may need to be increased by 30 minutes.
4.2.2General performance characteristics
652326
326163
Sustained transfer rate130 MiB/s **
136MB/s
SAS Interface maximum instantaneous transfer rate1200 MB/s* per port
Logical block sizes
512E & 512N - 512 (default), 520,524, or 528
4096N - 4096 (default), 4160, 4192, or 4224
Read/write consecutive sectors on a trackYe s
Flaw reallocation performance impact (for flaws reallocated at format time using the spare
sectors per sparing zone reallocation scheme.)
Average rotational latency4.167ms
(dual port = 2400 MB/s*)
Negligible
*Assumes no errors and no relocated logical blocks. Rate measured from the start of the first logical block transfer to or from the host.
** MiB/s x 1.048 = MB/s
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 13
4.3Start/stop time
The drive accepts the commands listed in the SAS Interface Manual less than 3 seconds after DC power has been applied.
If the drive receives a NOTIFY (ENABLE SPINUP) primitive through either port and has not received a START STOP UNIT command with the START bit
equal to 0, the drive becomes ready for normal operations within 20 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit equal to 0 before receiving a NOTIFY (ENABLE SPINUP) primitive, the drive
waits for a START STOP UNIT command with the START bit equal to 1. After receiving a START STOP UNIT command with the START bit equal to 1, the
drive waits for a NOTIFY (ENABLE SPINUP) primitive. After receiving a NOTIFY (ENABLE SPINUP) primitive through either port, the drive becomes
ready for normal operations within 20 seconds (excluding the error recovery procedure).
The START STOP UNIT command may be used to command the drive to stop the spindle. Stop time is 20 seconds (maximum) from removal of DC
power. SCSI stop time is 20 seconds. There is no power control switch on the drive. However, power can be cycled on the drive by utilizing SAS
Power Disable feature defined by T10 (i.e. drive Pin 3 high).
4.4Prefetch/multi-segmented cache control
The drive provides a prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system
performance. Cache refers to the drive buffer storage space when it is used in cache operations. To select this feature, the host sends the Mode
Select command with the proper values in the applicable bytes in page 08h. Prefetch and cache operations are independent features from the
standpoint that each is enabled and disabled independently using the Mode Select command; however, in actual operation, the prefetch feature
overlaps cache operation somewhat as described in sections 4.5.1 and 4.5.2.
All default cache and prefetch mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given in Section 11.3.2.
4.5Cache operation
Note
Of the 128MB physical buffer space in the drive, approximately 60,000KB are available as a data cache. The remaining buffer space is reserved for
internal drive use.
The drive keeps track of the logical block addresses of the data stored in each segment of the buffer. If the cache is enabled (see RCD bit in the SAS Interface Manual ), data requested by the host with a read command is retrieved from the buffer, if possible, before any disk access is initiated. If
cache operation is not enabled, the buffer is still used, but only as circular buffer segments during disk medium read operations (disregarding
Prefetch operation for the moment). That is, the drive does not check in the buffer segments for the requested read data, but goes directly to the
medium to retrieve it. The retrieved data merely passes through some buffer segment on the way to the host. All data transfers to the host are in
accordance with buffer-full ratio rules. See the explanation provided with the information about Mode Page 02h (disconnect/reconnect control) in
the SAS Interface Manual.
The following is a simplified description of the prefetch/cache operation:
Case A—read command is received and all of the requested logical blocks are already in the cache:
1.Drive transfers the requested logical blocks to the initiator.
Case B—A Read command requests data, and at least one requested logical block is not in any segment of the cache:
1.The drive fetches the requested logical blocks from the disk and transfers them into a segment, and then from there to the host in accordance
with the Mode Select Disconnect/Reconnect parameters, page 02h.
2.If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.
Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blocks. The drive dynamically creates
and removes segments based on the workload. The wrap-around capability of the individual segments greatly enhances the cache’s overall
performance.
Refer to the SAS Interface Manual for more detail concerning the cache bits.
The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15.
The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size
Note
specification using the Mode Select command (bytes 14 and 15) does not set up a new segment
size. If the STRICT bit in Mode page 00h (byte 2, bit 1) is set to one, the drive responds as it does
for any attempt to change an unchangeable parameter.
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 14
4.5.1Caching write data
Note
Note
Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to be written to the medium is stored
while the drive performs the Write command. WCE=0 provides NVC-protected write caching over a small portion of the DRAM.
If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made available for future read cache hits. The
same buffer space and segmentation is used as set up for read functions. The buffer segmentation scheme is set up or changed independently,
having nothing to do with the state of RCD. When a write command is issued, if RCD=0, the cache is first checked to see if any logical blocks that are
to be written are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The
new data is cached for subsequent Read commands.
If the number of write data logical blocks exceed the size of the segment being written into, when the end of the segment is reached, the data is
written into the beginning of the same cache segment, overwriting the data that was written there at the beginning of the operation; however, the
drive does not overwrite data that has not yet been written to the medium.
If write caching is enabled (WCE=1), then the drive may return Good status on a write command after the data has been transferred into the cache,
but before the data has been written to the medium. If an error occurs while writing the data to the medium, and Good status has already been
returned, a deferred error will be generated.
The Synchronize Cache command may be used to force the drive to write all cached write data to the medium. Upon completion of a Synchronize
Cache command, all data received from previous write commands will have been written to the medium. Section 11.3.2 shows the mode default
settings for the drive.
4.5.2Prefetch operation
Write caching in this section is the traditional SCSI write caching
(WCE=1) where writes are not protected on power loss.
Refer to the SAS Interface Manual for more detail concerning the cache bits.
If the Prefetch feature is enabled, data in contiguous logical blocks on the disk immediately beyond that which was requested by a Read command
are retrieved and stored in the buffer for immediate transfer from the buffer to the host on subsequent Read commands that request those logical
blocks (this is true even if cache operation is disabled). Though the prefetch operation uses the buffer as a cache, finding the requested data in the
buffer is a prefetch hit, not a cache operation hit.
To enable Prefetch, use Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch.
The drive does not use the Max Prefetch field (bytes 8 and 9) or the Prefetch Ceiling field (bytes 10 and 11).
When prefetch (read look-ahead) is enabled (enabled by DRA = 0), the drive enables prefetch of contiguous blocks from the disk when it senses that
a prefetch hit will likely occur. The drive disables prefetch when it decides that a prefetch hit is not likely to occur.
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 15
5.0Reliability specifications
The following reliability specifications assume correct host and drive operational interface, including all interface timings, power supply voltages,
environmental requirements and drive mounting constraints.
Seek error rate:Less than 10 errors in 108 seeks
Read Error Rates
Recovered DataLess than 10 error in 1012 bits transferred (OEM default settings)
Unrecovered DataLess than 1 sector in 10
Miscorrected DataLess than 1 sector in 10
Interface error rate:Less than 1 error in 10
Mean Time Between Failure (MTBF):2,000,000 hours
Annualized Failure Rate (AFR):0.44%
Preventive maintenance:None required
1.Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.
5.1Error rates
The error rates stated in this manual assume the following:
•The drive is operated in accordance with this manual using DC power as defined in paragraph 6.3, "DC power requirements."
•Errors caused by host system failures are excluded from error rate computations.
•Assume random data.
•Default OEM error recovery settings are applied. This includes AWRE, ARRE, full read retries, full write retries and full retry time.
1
15
bits transferred
21
bits transferred
12
bits transferred
5.1.1Recoverable Errors
Recoverable errors are those detected and corrected by the drive, and do not require user intervention.
Recoverable Data errors will use Error Correction when needed.
Recovered Data error rate is determined using read bits transferred for recoverable errors occurring during a read, and using write bits transferred
for recoverable errors occurring during a write.
5.1.2Unrecoverable Errors
An unrecoverable data error is defined as a failure of the drive to recover data from the media. These errors occur due to head/media or write
problems. Unrecoverable data errors are only detected during read operations, but not caused by the read. If an unrecoverable data error is
detected, a MEDIUM ERROR (03h) in the Sense Key will be reported. Multiple unrecoverable data errors resulting from the same cause are treated as
1 error.
5.1.3Seek errors
A seek error is defined as a failure of the drive to position the heads to the addressed track. After detecting an initial seek error, the drive
automatically performs an error recovery process. If the error recovery process fails, a seek positioning error (Error code = 15h or 02h) will be
reported with a Hardware error (04h) in the Sense Key. Recoverable seek errors are specified at Less than 10 errors in 10
errors (Sense Key = 04h) are classified as drive failures.
5.1.4Interface errors
An interface error is defined as a failure of the receiver on a port to recover the data as transmitted by the device port connected to the receiver. The
error may be detected as a running disparity error, illegal code, loss of word sync, or CRC error.
8
seeks. Unrecoverable seek
Seagate Enterprise Capacity 2.5 HDD v3 SAS Product Manual, Rev. E 16
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