Seagate ST973402SS, ST9146802SS Media Pre-Scan, Deferred Auto-Reallocation, Idle Read After Write

Page 50

Since the background scan functions are only done during idle periods, BMS causes a negligible impact to sys- tem performance. The first BMS scan for a newly manufactured drive is performed as quickly as possible to verify the media and protect data by setting the “Start time after idle” to 5ms, all subsequent scans begin after 500ms of idle time. Other features that normally use idle time to function will function normally because BMS functions for bursts of 800ms and then suspends activity for 100ms to allow other background functions to operate.

BMS interrupts immediately to service host commands from the interface bus while performing reads. BMS will complete any BMS-initiated error recovery prior to returning to service host-initiated commands. Overhead associated with a return to host-servicing activity from BMS only impacts the first command that interrupted BMS, this results in a typical delay of about 1 ms.

7.5Media Pre-Scan

Media Pre-Scan is a feature that allows the drive to repair media errors that would otherwise have been found by the host system during critical data accesses early in the drive’s life. The default setting for Media Pre-Scan is enabled on standard products. Media Pre-Scan checks each write command to determine if the destination LBAs have been scanned by BMS. If the LBAs have been verified, the drive proceeds with the normal write command. If the LBAs have not been verified by BMS, Pre-Scan will convert the write to a write verify to certify that the data was properly written to the disc.

Note. During Pre-Scan write verify commands, write performance may decrease by 50% until Pre-Scan completes. Write performance testing should be performed after Pre-Scan is complete. This may be checked by reading the BMS status.

To expedite the scan of the full pack and subsequently exit from the Pre-Scan period, BMS will begin scanning immediately when the drive goes to idle during the Pre-Scan period. In the event that the drive is in a high transaction traffic environment and is unable to complete a BMS scan within 24 power on hours BMS will dis- able Pre-Scan to restore full performance to the system.

7.6Deferred Auto-Reallocation

Deferred Auto-Reallocation (DAR) simplifies reallocation algorithms at the system level by allowing the drive to reallocate unreadable locations on a subsequent write command. Sites are marked for DAR during read oper- ations performed by the drive. When a write command is received for an LBA marked for DAR, the auto-reallo- cation process is invoked and attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

This is in contrast to the system having to use the Reassign Command to reassign a location that was unread- able and then generate a write command to rewrite the data. DAR is most effective when AWRE and ARRE are enabled—this is the default setting from the Seagate factory. With AWRE and ARRE disabled DAR is unable to reallocate the failing location and will report an error sense code indicating that a write command is being attempted to a previously failing location.

7.7Idle Read After Write

Idle Read After Write (IRAW) utilizes idle time to verify the integrity of recently written data. During idle periods, no active system requests, the drive reads recently written data from the media and compares it to valid write command data resident in the drives data buffer. Any sectors that fail the comparison result in the invocation of a rewrite and auto-reallocation process. The process attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

40

Savvio 10K.2 SAS Product Manual, Rev. B

Page 49 Page 51
Image 50
Page 49 Page 51
Contents Savvio 10K.2 SAS Page Savvio 10K.2 SAS Page Revision status summary sheet Revision DatePage Contents Seagate Technology support services Defect and error managementInstallation Interface requirementsList of Figures Savvio 10K.2 SAS disc drivePage Scope Savvio 10K.2 SAS disc driveSavvio 10K.2 SAS Product Manual, Rev. B Electromagnetic compatibility Applicable standards and reference documentationStandards Electromagnetic susceptibilityAustralian C-Tick Electromagnetic complianceElectromagnetic compliance for the European Union Korean MICReference documents European Union Restriction of Hazardous Substances RoHSSavvio 10K.2 SAS Product Manual, Rev. B General description Performance Standard featuresMedia description Formatted capacities Factory-installed accessoriesReliability Programmable drive capacityFactory-installed options Seek performance characteristics Performance characteristicsInternal drive characteristics Access timeFormat command execution time for 512-byte sectors minutes General performance characteristicsCache operation Start/stop timePrefetch/multi-segmented cache control Caching write data Prefetch operationPage Savvio 10K.2 SAS Product Manual, Rev. B Recoverable Errors Reliability specificationsError rates Unrecoverable ErrorsInterface errors Reliability and serviceSeek errors Preventive maintenancePerformance impact 4 S.M.A.R.TControlling S.M.A.R.T MillisecondsPredictive failures Reporting controlDetermining rate Thermal monitorDST failure definition Temperature Log Page 0Dh Parameter Code DescriptionDrive Self Test DST ImplementationShort and extended tests State of the drive prior to testingInvoking DST Short test Function Code 001bAbort Product warrantyLog page entries ShippingProduct repair and return information DC power requirements Physical/electrical specificationsAC power requirements ST9146802SS DC power requirementsST973402SS Gbit mode Amps ST973402SS DC power requirementsGeneral DC power requirement notes Current profiles Power sequencingConducted noise immunity +5V +12VST973402SS current profile ST973402SS in 3 Gbit operation Power dissipationST9146802SS in 3 Gbit operation Temperature Environmental limitsShock and vibration Relative humidityEffective altitude sea level ShockPackage size Packaged/product weight Drop height Recommended mountingCorrosive environment Air cleanlinessVibration Acoustics Mechanical specifications Mounting configuration dimensionsSavvio 10K.2 SAS Product Manual, Rev. B Drive error recovery procedures Defect and error managementDrive internal defects/errors Page SAS system errors Background Media ScanIdle Read After Write Media Pre-ScanDeferred Auto-Reallocation Installation Drive orientationCooling Air flowDrive mounting GroundingSavvio 10K.2 SAS Product Manual, Rev. B SAS features Interface requirementsDual port support Command name Command code Supported Scsi commands supportedCommands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Savvio inquiry data Mode Sense dataInquiry data Bytes Data hexPage Mode Data Header 08 8b b9 98 00 00 02 Supported Feature or condition Miscellaneous operating features and conditionsMiscellaneous features Miscellaneous statusSAS physical interface Datum B Section C C Section a a Electrical description Physical characteristicsConnector requirements Pin descriptionsSAS transmitters and receivers Signal characteristicsPower Ready LED OutGeneral interface characteristics LED drive signalDifferential signals Eye masks Eye masks overviewReceive eye mask Jitter tolerance masksJitter Peak-toSinusoidal Frequency in kHzTransmitter signal characteristics Signal characteristica Units GbpsMaximum allowable jitter Receiver signal characteristicsSignal characteristic Units Gbps Gbps m, n Deterministic jitterqCompliant jitter test pattern Cjtpat Impedance specificationsReceiver jitter tolerance Impedance requirements Sheet 1Electrical TxRx connections Transmitter characteristicsImpedance requirements Sheet 2 = -5,437dB Tctf Receiver characteristics ISI loss example at 1.5 GbpsInternet MySeagate Spp.seagate.com Seagate Technology support servicesWarranty Service Presales SupportData Recovery Services Authorized Service Centers Data Recovery ServicesToll-free support numbers FAX services-All Europe toll callCall center Presales and Technical Support Warranty Service Seagate Service Centers Index NumericsPage SAS See also cooling Page Seagate Technology LLC
Related manuals
Manual 84 pages 36.64 Kb

ST973402SS, ST9146802SS specifications

The Seagate ST973402SS and ST9146802SS are high-performance, enterprise-grade hard drives designed to meet the demanding needs of data-intensive applications. These drives are part of Seagate's Savvio and Barracuda product lines, aimed specifically at businesses and institutions requiring reliability, speed, and efficiency in storage solutions.

The ST973402SS is a 73GB, 2.5-inch hard drive, while the ST9146802SS offers a larger capacity of 146GB. Both models utilize a 10,000 RPM spindle speed, which significantly enhances their ability to handle fast data read and write operations. This speed ensures reduced latency and improved overall performance, making them ideal for environments where rapid access to data is crucial.

One of the standout features of these drives is their support for Serial Attached SCSI (SAS) interface. SAS technology provides a point-to-point connection, which allows for increased data transfer rates compared to traditional SATA drives. The ST973402SS and ST9146802SS are capable of transferring data at speeds of up to 600 MB/s, facilitating efficient data transfers in enterprise systems.

In terms of reliability, both models offer advanced features designed to improve data integrity and durability. They are built to withstand high workloads, with an annualized workload rate of up to 550 TB per year. This makes them well-suited for applications like databases and transactional storage, where sustained performance is required. Additionally, the drives feature Seagate’s PowerFit technology, which optimizes performance while minimizing power consumption.

To enhance data security, the drives come equipped with self-encrypting technology, ensuring that sensitive data is protected through hardware-based encryption. This is particularly important in environments where data breaches can lead to significant operational impacts.

The drives are also designed to operate efficiently in terms of thermal management, featuring robust heat dissipation capabilities. This helps to maintain optimal performance levels while prolonging the lifespan of the drives.

Overall, the Seagate ST973402SS and ST9146802SS are robust and reliable hard drives that cater to the needs of enterprise environments, combining high capacity, exceptional speed, advanced security features, and energy efficiency to help businesses maintain and manage large volumes of data effectively. With their proven performance and innovative technologies, these drives are well-equipped to support a wide range of applications in modern data centers.
Top Page Image Contents