Publication number: 200562600, Rev. A November 2023
Seagate, Seagate Technology and the Spiral logo are registered trademarks of Seagate Technology LLC in the United States and/or other countries. Raid Rebuild and
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 reserves the right to
change, without notice, product offerings or specifications.
For Seagate Product Support, visit: www.seagate.com/support
For Seagate Compliance, Safety, and Disposal, visit: www.seagate.com/support
For Firmware Download and Tools Download for Secure Erase, visit: www.seagate.com/support/downloads/
For information regarding online support and services, visit: www.seagate.com/contacts/
For information regarding Warranty Support, visit: www.seagate.com/support/warranty-and-replacements/
For information regarding data recovery services, visit: www.seagate.com/services-software/recover/resources/
For Seagate OEM and Distribution partner and Seagate reseller portal, visit: www.seagate.com/partners
Seagate Exos X24 SAS Product Manual, Rev. A 5
www.seagate.comScope
1.0Scope
This manual describes Seagate® Exos® X24 SAS (Serial Attached SCSI) disk drives.
Exos X24 drives support the SAS Protocol specifications to the extent described in this manual. The SAS Interface Manual (part number
10029xxx) describes the general SAS characteristics of this and other Seagate SAS drives.
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 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 in “Seagate® Technology Support Services” on page 5.
Unless otherwise stated, the information in this manual applies to standard and Self-Encrypting Drive models.
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).
Seagate Exos X24 SAS Product Manual, Rev. A6
www.seagate.comHDD and SSD Regulatory Compliance and Safety
2.0HDD and SSD Regulatory Compliance and Safety
For the latest regulatory and compliance information see:www.seagate.com/support scroll down the page and click the
Compliance, Safety and Disposal Guide link.
2.0.1Regulatory Models
The following regulatory model number represent all features and configurations within the series:
Specification for Acoustic Test Requirement and Procedures
Seagate part number: 30553-001
In case of conflict between this document and any referenced document, this document takes precedence.
Seagate Exos X24 SAS Product Manual, Rev. A7
www.seagate.comGeneral description
3.0General description
Exos X24 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.
Exos X24 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 M anu al (part number 100293071) which describes the gen eral interface
characteristics of this drive. Exos X24 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 users 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.trustedcomputin
The head and disk assembly (HDA) is sealed at the factory. Helium recirculates within the HDA through a non-replaceable filter to
maintain a contamination-free HDA environment.
Never disassemble the HDA and do not attempt to service items in the sealed enclosure
Note
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.
Exos X24 drives decode track 0 location data from the servo data embedded on each surface to eliminate mechanical transducer
adjustments and related reliability concerns.
(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 product
warranty.
ggroup.org).
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.
Note
Seagate recommends validating the configuration with the selected HBA/RAID
controller manufacturer to ensure use of full capacity is supported.
Seagate Exos X24 SAS Product Manual, Rev. A8
www.seagate.comGeneral description
3.1Standard features
Exos X24 drives have the following standard features:
• 128 - deep task set (queue)
• 512MB data buffer (See Section 4.4) .
• 3.0 / 6.0/12.0 Gb Serial Attached SCSI (SAS) interface
• Drive Self Test (DST)
• Embedded servo design
• Firmware downloadable using the SAS interface
• Flawed logical block reallocation at format time
• Industry standard SFF 3.5-in dimensions
• Integrated dual port SAS controller supporting the SCSI protocol
• No preventive maintenance or adjustments required
• Perpendicular recording technology
• Power Balance supported (see Section 6.2 on page 23)
• Programmable auto write and read reallocation
• Programmable logical block reallocation scheme
• 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 32 initiators
• T10 Fast Format supported (see Section 4.1.2)
• User-selectable logical block sizes for 4096 native models (4096, 4160 bytes per logical block)
• User-selectable logical block sizes for 512E (512, 520 bytes per logical block).
• Vertical, horizontal, or top down mounting
Seagate Exos X24 SAS Self-Encrypting Drive models have the following additional features:
• 32 Independent data bands
• Authenticated firmware download
• Automatic data encryption/decryption
• Controlled access
• Cryptographic erase of user data for a drive that will be re-purposed or scrapped
• 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.
3.3Reliability
• 5-year warranty
• Annualized Failure Rate (AFR) of 0.35%
• 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 2,500,000 hours
Seagate Exos X24 SAS Product Manual, Rev. A9
www.seagate.comGeneral description
3.4Media description
The media used on the drive has a glass substrate coated with a thin film magnetic material, over coated with a proprietary protective
layer for improved durability and environmental protection.
3.5Formatted capacities
Standard OEM models are formatted to 512 bytes per block for 512 emulation drives and 4096 bytes per block for 4096 native drives.
The block size is selectable at format time. Supported block sizes are 512, 520 for 512 emulation drives and 4096, 4160 for 4096 native
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 shown below.
Sector
Size
512
520
4096
4160
Sector
Size
512
520
4096
4160
Note
24TB with PI bytes24TB w/out PI bytes20TB with PI bytes20TB w/out PI bytes
LBA Counts for drive capacities greater than 8TB are calculated based upon
teh SFF-8447 standard publication.
Seagate Exos X24 SAS Product Manual, Rev. A10
www.seagate.comGeneral description
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
Users may order the following items 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 number75789512, is usually included with each standard OEM drive shipped,
but extra copies may be ordered.
Seagate Exos X24 SAS Product Manual, Rev. A11
www.seagate.comPerformance characteristics
4.0Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of Exos X24 drives.
4.1Internal drive characteristics
Drive capacity24TB20TB16TB12TB(formatted, rounded off value)
Read/write data heads 20 18 15 11
Bytes/track1,956,3091,907,4011,858,4941,956,309Bytes (average, rounded off values)
Bytes/surface1,000,0001,170,0001,140,0001,200,000MB (unformatted, rounded off values)
Tracks/surface (total)613,400613,400613,400613,400Tracks (user accessible)
Tracks/in536,000536,000536,000536,000TPI (average)
Peak bits/in2,477,6122,477,6122,477,6122,477,612BPI
Areal density1362132812941362Gb/in2
Internal data rate3104302629493104Mb/s (max)
Disk rotation speed7200720072007200RPM
Avg rotational latency4.164.164.164.16ms
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.
4.1.2Fast Format
Drive sector size transition
• Single code to support sector sizes from 512E
• T10 fast format conversion between 512E configurations in the field.
• Possible only if sector sizes are exact multiples of 8 & vice versa
• The selected sector size will take effect only after fast format or full format
• Drive default is 512E from the factory.
• 512E features set after Fast Format
T10 Fast Format
• Implements the fast format based on T10 Spec.
• To request Fast Format, the FFMT bits (Byte 4, Bits 1:0) should be set to 01b.
• A setting of 10b or 11b will return a check condition with 05/24 sense code (pointing to FFMT MSB in CDB).
Mode Select - Parameter list header
• Set Write buffer: // Set Block Descriptor Length = 0x08, Number of LBAs = 0xFFFFFFFF
• cdb: 04 14 00 00 01 00 // (FMTDAT = 1, DEFECT LIST FORMAT = 010b, FFMT = 01b)
41903352
20961676
25161886
1257943
Seagate Exos X24 SAS Product Manual, Rev. A12
www.seagate.comPerformance characteristics
4.1.3General performance characteristics
Minimum sector interleave1 to 1
Maximum Internal data rate*2.7 Gb/s
Sustained transfer rate132 to 272 MiB/s **
SAS Interface maximum instantaneous transfer rate1200MB/s* per port
Logical block sizes
512 (default), 520.
4096, 4160.
Read/write consecutive sectors on a trackYes
Flaw reallocation performance impact (for flaws reallocated at format time using the
spare sectors per sparing zone reallocation scheme.)
Average rotational latency4.16ms
*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
(dual port = 2400MB/s*)
Negligible
4.2Start/stop time
Power-on to ready time is based on typical operating conditions, default full current spin-up profile, and clean shutdown prior to
measurement. To ensure a clean shutdown issue a START STOP UNIT command with the START bit set to zero and the IMMED bit set
to zero, so that the device will return status after the operation is completed.
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 n ormal ope rations within 30 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 30 seconds (excluding the error recovery
procedure).
If the drive receives a START STOP UNIT command with the START bit and IMMED bit equal to 1 and does not receive a NOTIFY
(ENABLE SPINUP) primitive within 5 seconds, the drive fails the START STOP UNIT command.
The START STOP UNIT command may be used to command the drive to stop the spindle. Stop time is 23 seconds (maximum) from
removal of DC power. SCSI stop time is 23 seconds. There is no power control switch on the drive.
An unexpected power loss event, spin up at cold or hot temperature extremes may cause the drive to exceed the typical and max time to
ready by 5 seconds. Extended time to ready is dependent on cache state and environmental conditions prior to the unexpected power
loss and during the subsequent power on.
Seagate Exos X24 SAS Product Manual, Rev. A13
www.seagate.comPerformance characteristics
4.3Prefetch/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 Table 4.4.1 and Table 4.4.2.
All default cache and prefetch mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given inTable
8.
4.4Cache operation
.
NoteRefer to the SAS Interface Manual for more detail concerning the cache bits.
The buffer is divided into logical segments from which data is read and to which data is written.
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 Table 4.4.2 for operation from this point.
Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blo cks. The dri ve
dynamically creates and removes segments based on the workload. The wrap-around capability of the individual segments greatly
enhances the cache’s overall performance.
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 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 Exos X24 SAS Product Manual, Rev. A14
www.seagate.comPerformance characteristics
4.4.1Caching write data
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.
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. Table 8 shows the
mode default settings for the drive.
4.4.2Prefetch operation
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 Exos X24 SAS Product Manual, Rev. A15
www.seagate.comReliability specifications
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.
8
Seek error rate:Less than 10 errors in 10
Read Error Rates
1
Recovered DataLess than 10 errors in 10
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):2,500,000 hours
Annualized Failure Rate (AFR):
2
0.35%
Preventive maintenance:None required
1.Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.
2.See Section 5.2, "Reliability and service" for rated MTBF device operating condition requirements.
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 Section 6.4, 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.
seeks
12
bits transferred (OEM default settings)
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 correction, although ECC on-the-fly is not considered for purposes of recovered error specifications.
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
seeks. Unrecoverable seek 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
Seagate Exos X24 SAS Product Manual, Rev. A16
www.seagate.comReliability specifications
5.2Reliability and service
Users can enhance the reliability of Exos X24 disk drives by ensuring that the drive receives adequate cooling. Section 6.0 provides
temperature measurements and other information that may be used to enhance the service life of the drive. Section 10.2 provides
recommended air-flow information.
5.2.1Annualized Failure Rate (AFR) and Mean Time Between Failure (MTBF)
The production disk drive shall achieve an annualized failure-rate of 0.35% (MTBF of 2,500,000 hours) over a 5 year service life when
used in Enterprise Storage field conditions as limited by the following:
• 8760 power-on hours per year.
• HDA temperature as reported by the drive >=10°C to <= 30°C
• Ambient wet bulb temp <= 26°C
• Typical workload
• The AFR (MTBF) is a population statistic not relevant to individual units
• ANSI/ISA S71.04-2013 G2 classification levels and dust contamination to ISO 14644-1 Class 8 standards (as measured at the device)
The MTBF specification for the drive assumes the operating environment is designed to maintain nominal drive temperature and
humidity. Occasional excursions in operating conditions between the rated MTBF conditions and the maximum drive operating conditions
may occur without significant impact to the rated MTBF. However continual or sustained operation beyond the rated MTBF conditions will
degrade the drive MTBF and reduce product reliability.
Nonrecoverable read errors1 per 10
Load unload cycles600,000 cycles
Maximum Rated WorkloadMaximum rate of <550TB/year. Workloads exceeding the annualized rate may degrade
Warranty
Preventive maintenanceNone required.
the drive MTBF and impact product reliability. The Annualized Workload Rate is in units
of TB per year, or TB per 8760 power on hours. Workload Rate = TB transferred * (8760
/ recorded power on hours).
To determine the warranty for a specific drive, use a web browser to access the following
web page: www.sea
From this page, click on the “Is my Drive under Warranty” link. The following are required
to be provided: the drive serial number, model number (or part number) and country of
purchase. The system will display the warranty information for the drive.
15
bits read, max
gate.com/support/warranty-and-replacements/.
5.2.2Hot plugging the drive
When a disk is powered on by switching the power or hot plugged, the drive runs a self test before attempting to communicate on its’
interfaces. When the self test completes successfully, the drive initiates a Link Reset starting with OOB. An attached device should
respond to the link reset. If the link reset attempt fails, or any time the drive looses sync, the drive initiated link reset. The drive will initiate
link reset once per second but alternates between port A and B. Therefore each port will attempt a link reset once per 2 seconds
assuming both ports are out of sync.
If the self-test fails, the drive does not respond to link reset on the failing port.
It is the responsibility of the systems integrator to assure that no temperature, energy, voltage hazard, or ESD potential hazard is
presented during the hot connect/disconnect operation. Discharge the static electricity from the drive carrier prior to inserting it into the
system.
Caution
Seagate Exos X24 SAS Product Manual, Rev. A17
The drive motor must come to a complete stop prior to changing the
plane of operation. This time is required to insure data integrity.
www.seagate.comReliability specifications
5.2.3S.M.A.R.T.
S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended to recognize conditions
that indicate imminent drive failure and is designed to provide sufficient warning of a failure to allow users to back up the data before an
actual failure occurs.
Note
Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating performance of the drive and
the thresholds are optimized to minimize “false” and “failed” predictions.
The drive’s firmware monitors specific attributes for degradation over time but
can’t predict instantaneous drive failures.
Controlling S.M.A.R.T.
The operating mode of S.M.A.R.T. is controlled by the DEXCPT and PERF bits on the Informational Exceptions Control mode page
(1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEXCPT bit disables all S.M.A.R.T. functions. When
enabled, S.M.A.R.T. collects on-line data as the drive performs normal read and write operations. When the PERF bit is set, the drive is
considered to be in “On-line Mode Only” and will not perform off-line functions.
Users can measure off-line attributes and force the drive to save the data by using the Rezero Unit command. Forcing S.M.A.R.T. resets
the timer so that the next scheduled interrupt is in one hour.
Users can interrogate the drive through the host to determine the time remaining before the next scheduled measurement and data
logging process occurs. To accomplish this, issue a Log Sense command to log page 0x3E. This allows the user to control when
S.M.A.R.T. interruptions occur. Forcing S.M.A.R.T. with the RTZ command resets the timer.
Performance impact
S.M.A.R.T. attribute data is saved to the disk so that the events that caused a predictive failure can be recreated. The drive measures
and saves parameters once every one hour subject to an idle period on the drive interfaces. The process of measuring off-line attribute
data and saving data to the disk is interruptible. The maximum on-line only processing delay is summarized below:
Maximum processing delay
Fully-enabled delay DEXCPT = 0
S.M.A.R.T. delay times75 ms
Reporting control
Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). An example, if the MRIE is set to one,
the firmware will issue to the host an 01-5D00 sense code. The FRU field contains the type of predictive failure that occurred. The error
code is preserved through bus resets and power cycles.
Determining rate
S.M.A.R.T. monitors the rate at which errors occur and signals a predictive failure if the rate of degraded errors increases to an
unacceptable level. To determine rate, error events are logged and compared to the number of total operations for a given attribute. The
interval defines the number of operations over which to measure the rate. The counter that keeps track of the current number of
operations is referred to as the Interval Counter.
S.M.A.R.T. measures error rates. All errors for each monitored attribute are recorded. A counter keeps track of the number of errors for
the current interval. This counter is referred to as the Failure Counter.
Error rate is the number of errors per operation. The algorithm that S.M.A.R.T. uses to record rates of error is to set thresholds for the
number of errors and their interval. If the number of errors exceeds the threshold before the interval expires, the error rate is considered
to be unacceptable. If the number of errors does not exceed the threshold before the interval expires, the error rate is considered to be
acceptable. In either case, the interval and failure counters are reset and the process starts over.
Seagate Exos X24 SAS Product Manual, Rev. A18
www.seagate.comReliability specifications
Predictive failures
S.M.A.R.T. signals predictive failures when the drive is performing unacceptably for a period of time. The firmware keeps a running count
of the number of times the error rate for each attribute is unacceptable. To accomplish this, a counter is incremented each time the error
rate is unacceptable and decremented (not to exceed zero) whenever the error rate is acceptable. If the counter continually increments
such that it reaches the predictive threshold, a predictive failure is signaled. This counter is referred to as the Failure History Counter.
There is a separate Failure History Counter for each attribute.
5.2.4Thermal monitor
Exos X24 drives implement a temperature warning system which:
1.Signals the host if the temperature exceeds a value which would threaten the drive.
2.Saves a S.M.A.R.T. data frame on the drive which exceeds the threatening temperature value.
A temperature sensor monitors the drive temperature and issues a warning over the interface when the temperature exceeds a set
threshold. The temperature is measured at power-up and then at ten-minute intervals after power-up.
The thermal monitor system generates a warning code of 01-0B01 when the temperature exceeds the specified limit in compliance with
the SCSI standard.
This feature is controlled by the Enable Warning (EWasc) bit, and the reporting mechanism is controlled by the Method of Reporting
Informational Exceptions field (MRIE) on the Informational Exceptions Control (IEC) mode page (1Ch).
5.2.5Drive Self Test (DST)
Drive Self Test (DST) is a technology designed to recognize drive fault conditions that qualify the drive as a failed unit. DST validates the
functionality of the drive at a system level.
There are two test coverage options implemented in DST:
1.Extended test
2.Short test
The most thorough option is the extended test that performs various tests on the drive and scans every logical block address (LBA) of the
drive. The short test is time-restricted and limited in length—it does not scan the entire media surface, but does some fundamental tests
and scans portions of the media.
If DST encounters an error during either of these tests, it reports a fault condition. If the drive fails the test, remove it from service and
return it to Seagate for service.
5.2.5.1DST failure definition
The drive will present a “diagnostic failed” condition through the self-tests results value of the diagnostic log page if a functional failure is
encountered during DST. The channel and servo parameters are not modified to test the drive more stringently, and the number of retries
are not reduced. All retries and recovery processes are enabled during the test. If data is recoverable, no failure condition will be reported
regardless of the number of retries required to recover the data.
The following conditions are considered DST failure conditions:
• Seek error after retries are exhausted
• Track-follow error after retries are exhausted
• Read error after retries are exhausted
• Write error after retries are exhausted
Recovered errors will not be reported as diagnostic failures.
Seagate Exos X24 SAS Product Manual, Rev. A19
www.seagate.comReliability specifications
5.2.5.2Implementation
This section provides all of the information necessary to implement the DST function on this drive.
5.2.5.2.1State of the drive prior to testing
The drive must be in a ready state before issuing the Send Diagnostic command. There are multiple reasons why a drive may not be
ready, some of which are valid conditions, and not errors. For example, a drive may be in process of doing a format, or another DST. It is
the responsibility of the host application to determine the “not ready” cause.
While not technically part of DST, a Not Ready condition also qualifies the drive to be returned to Seagate as a failed drive.
A Drive Not Ready condition is reported by the drive under the following conditions:
• Motor will not spin
• Motor will not lock to speed
• Servo will not lock on track
• Drive cannot read configuration tables from the disk
In these conditions, the drive responds to a Test Unit Ready command with an 02/04/00 or 02/04/03 code.
5.2.5.2.2Invoking DST
To invoke DST, submit the Send Diagnostic command with the appropriate Function Code (001b for the short test or 010b for the
extended test) in bytes 1, bits 5, 6, and 7.
5.2.5.2.3Short and extended tests
DST has two testing options:
1.short
2.extended
These testing options are described in the following two subsections.
Each test consists of three segments: an electrical test segment, a servo test segment, and a read/verify scan segment.
Short test (Function Code: 001b)
The purpose of the short test is to provide a time-limited test that tests as much of the drive as possible within 120 seconds. The short
test does not scan the entire media surface, but does some fundamental tests and scans portions of the media. A complete read/verify
scan is not performed and only factual failures will report a fault condition. This option provides a quick confidence test of the drive.
Extended test (Function Code: 010b)
The objective of the extended test option is to empirically test critical drive components. For example, the seek tests and on-track
operations test the positioning mechanism. The read operation tests the read head element and the media surface. The write element is
tested through read/write/read operations. The integrity of the media is checked through a read/verify scan of the media. Motor
functionality is tested by default as a part of these tests.
The anticipated length of the Extended test is reported through the Control Mode page.
Seagate Exos X24 SAS Product Manual, Rev. A20
www.seagate.comReliability specifications
5.2.5.2.4Log page entries
When the drive begins DST, it creates a new entry in the Self-test Results Log page. The new entry is created by inserting a new self-test
parameter block at the beginning of the self-test results log parameter section of the log page. Existing data will be moved to make room
for the new parameter block. The drive reports 20 parameter blocks in the log page. If there are more than 20 parameter blocks, the least
recent parameter block will be deleted. The new parameter block will be initialized as follows:
1. The Function Code field is set to the same value as sent in the DST command
2. The Self-Test Results Value field is set to Fh
3. The drive will store the log page to non-volatile memory
After a self-test is complete or has been aborted, the drive updates the Self-Test Results Value field in its Self-Test Results Log page in
non-volatile memory. The host may use Log Sense to read the results from up to the last 20 self-tests performed by the drive. The selftest results value is a 4-bit field that reports the results of the test. If the field is set to zero, the drive passed with no errors detected by the
DST. If the field is not set to zero, the test failed for the reason reported in the field.
The drive will report the failure condition and LBA (if applicable) in the Self-test Results Log parameter. The Sense key, ASC, ASCQ, and
FRU are used to report the failure condition.
5.2.5.2.5Abort
There are several ways to abort a diagnostic. Users can use a SCSI Bus Reset or a Bus Device Reset message to abort the diagnostic.
Users can abort a DST executing in background mode by using the abort code in the DST Function Code field. This will cause a 01 (selftest aborted by the application client) code to appear in the self-test results values log. All other abort mechanisms will be reported as a
02 (self-test routine was interrupted by a reset condition).
5.2.6Product warranty
See “Seagate® Technology Support Services” on page 5 for warranty contact information.
Shipping
When transporting or shipping a drive, use only a Seagate-approved container. Keep the original box. Seagate approved containers are
easily identified by the Seagate Approved Package label. Shipping a drive in a non-approved container voids the drive warranty.
Seagate repair centers may refuse receipt of components improperly packaged or obviously damaged in transit. Contact the authorized
Seagate distributor to purchase additional boxes. Seagate recommends shipping by an air-ride carrier experienced in handling computer
equipment.
Storage
Maximum storage periods are 180 days within original unopened Seagate shipping package or 60 days unpackaged within the defined
non-operating limits (refer to environmental section in this manual). Storage can be extended to 1 year packaged or unpackaged under
optimal environmental conditions (25°C, <40% relative humidity non-condensing, and non-corrosive environment). During any storage
period the drive non-operational temperature, humidity, wet bulb, atmospheric conditions, shock, vibration, magnetic and electrical field
specifications should be followed.
Product repair and return information
Seagate customer service centers are the only facilities authorized to service Seagate drives. Seagate does not sanction any third-party
repair facilities. Any unauthorized repair or tampering with the factory seal voids the warranty.
Seagate Exos X24 SAS Product Manual, Rev. A21
www.seagate.comPhysical/electrical specifications
6.0Physical/electrical specifications
This section provides information relating to the physical and electrical characteristics of the drive.
6.1PowerChoice™ power management
Drives using the load/unload architecture provide programmable power management to tailor systems for performance and greater
energy efficiency.
The table below lists the supported PowerChoice modes. The further down the user goes in the table, the more power savings the user
gets. For example, Idle_B mode results in greater power savings than Idle_A mode. Standby_Z mode results in the greatest power
savings.
PowerChoice modes
ModeDescription
Idle_AReduced electronics
Idle_BHeads unloaded. Disks spinning at full RPM
Idle_CHeads unloaded. Disks spinning at reduced RPM
Standby_YHeads unloaded. Disks spinning at reduced RPM.
Standby_ZHeads unloaded. Motor stopped (disks not spinning)
PowerChoice can be invoked using one of these two methods:
• Power Condition mode page method—Enable and initialize the idle condition timers and/or the standby condition timers. The timer val-
ues are based on the values set in the Power Condition mode page.
• START STOP UNIT command method—Use the START STOP UNIT command (OPERATION CODE 1Bh). This allows the host to
directly transition the drive to any supported PowerChoice mode.
If both the Power Condition mode page and START STOP UNIT command methods are used, the START STOP UNIT command request
takes precedence over the Power Condition mode page power control and may disable the idle condition and standby condition timers.
The REQUEST SENSE command reports the current PowerChoice state if active and also the method by which the drive entered the
PowerChoice state.
When the drive receives a command, all power condition timers are suspended if they were enabled via the Power Condition mode page.
Once all outstanding commands are processed, the power condition timers are reinitialized to the values defined in the Power Condition
mode page
Recovery requires the NOTIFY (Enable Spinup) command.
Recovery requires the NOTIFY (Enable Spinup) command.
Seagate Exos X24 SAS Product Manual, Rev. A22
www.seagate.comPhysical/electrical specifications
6.1.1PowerChoice reporting methods
PowerChoice provides these reporting methods for tracking purposes:
Request Sense command reports
• Current power condition
• Method of entry
.
Note Processing the Request Sense command does not impact the drive’s power save state.
• Accumulated transitions to Active, Idle_A, Idle_B, Idle_C, Standby_Y, Standby_Z
6.2Power Balance
• Mode page 01h byte 6 bits 0 & 1 define the Active Level
• Active Levels - 00b Default,11b Lowest active power level
6.3AC power requirements
None.
Seagate Exos X24 SAS Product Manual, Rev. A23
www.seagate.comPhysical/electrical specifications
6.4DC power requirements
The voltage and current requirements for a single drive are shown below. Values indicated apply at the drive connector.
The standard drive models and the SED drive models have identical hardware, however the security and encryption portion of the drive
controller ASIC is enabled and functional in the SED models. This represents a small additional drain on the 5V supply of about 30mA
and a commensurate increase of about 150mW in power consumption. There is no additional drain on the 12V supply.
Table 1 DC power requirements (24TB and 20TB models)