Seagate ST91000642SS, ST9500621SS, ST9500620SS, ST9500622SS, 100620418 manual SAS system errors

Page 53

The drive firmware error recovery algorithms consist of 20 levels for read recoveries and five levels for write. Each level may consist of multiple steps, where a step is defined as a recovery function involving a single re- read or re-write attempt. The maximum level used by the drive in LBA recovery is determined by the read and write retry counts.

Table 4 equates the read and write retry count with the maximum possible recovery time for read and write recovery of individual LBAs. The times given do not include time taken to perform reallocations. Reallocations are performed when the ARRE bit (for reads) or AWRE bit (for writes) is one, the RC bit is zero, and the recov- ery time limit for the command has not yet been met. Time needed to perform reallocation is not counted against the recovery time limit.

When the RC bit is one, reallocations are disabled even if the ARRE or AWRE bits are one. The drive will still perform data recovery actions within the limits defined by the Read Retry Count, Write Retry Count, and Recovery Time Limit parameters. However, the drive does not report any unrecovered errors.

Table 4: Read and write retry count maximum recovery times

 

Maximum recovery time per

Read retry count*

LBA (cumulative, msec)

 

 

 

 

1

124.32

 

 

5

621.62

 

 

10

1243.23

 

 

15

1864.85

 

 

20 (default)

2486.47

 

 

Write retry count

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

33.32

 

 

1

74.97

 

 

2

103.92

 

 

3

128.91

 

 

4

220.09

 

 

5 (default)

278.40

 

 

*For read retry count, every tick ~ 5% of total error recovery. Valid range setting is 1-20. e.g. 1 ~ 5%

5 ~ 25%

20 ~ 100%

Setting these retry counts to a value below the default setting could result in degradation of the unrecovered error rate. For example, suppose the read/write recovery page has the RC bit = 0 and if the read retry count is set to 5, this means ~ 25% of error recovery will be executed which consumes 621.62 ms (please refer to the table above). If the limit is reached and a LBA has not yet been recovered (i.e. requires retries beyond 621.62 ms), the command will end with Check Condition status report and unrecoverable read error will be reported.

10.3SAS system errors

Information on the reporting of operational errors or faults across the interface is given in the SAS Interface Manual. The SSP Response returns information to the host about numerous kinds of errors or faults. The Receive Diagnostic Results reports the results of diagnostic operations performed by the drive.

Status returned by the drive to the initiator is described in the SAS Interface Manual. Status reporting plays a role in systems error management and its use in that respect is described in sections where the various com- mands are discussed.

Constellation.2 SAS Product Manual, Rev. H

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Contents ST91000642SS ST9500622SS ST91000640SSST91000641SS ST9500620SSST9500621SSStandard Models Self-Encrypting Drive Models SED Fips 140-2 ModelsRevision history Contents Installation Defect and error managementAbout Fips About self-encrypting drives Interface requirementsPage Constellation.2 SAS Product Manual, Rev. H List of Figures Constellation.2 SAS Product Manual, Rev. H Seagate Online Support and Services Seagate Technology support servicesScope Standards Applicable standards and reference documentationElectromagnetic compatibility Electromagnetic susceptibilityElectromagnetic compliance for the European Union Electromagnetic complianceAustralian C-Tick Korean KCCChina Restriction of Hazardous Substances RoHS Directive European Union Restriction of Hazardous Substances RoHSSelf-Encrypting Drives Reference Manual Reference documentsGeneral description Media description Standard featuresReliability PerformanceFormatted capacities Programmable drive capacityFactory-installed options Internal drive characteristics Performance characteristicsSeek performance characteristics Access timeStart/stop time General performance characteristicsCache operation Prefetch/multi-segmented cache controlPrefetch operation Caching write dataError rates Reliability specificationsRecoverable Errors Unrecoverable ErrorsSeek errors Reliability and serviceInterface errors Preventive maintenanceControlling S.M.A.R.T 4 S.M.A.R.TPerformance impact Reporting controlThermal monitor Temperature Log Page 0Dh Parameter Code DescriptionPredictive failures Drive Self Test DST State of the drive prior to testingDST failure definition ImplementationShort test Function Code 001b Short and extended testsExtended test Function Code 010b Log page entriesShipping Product warrantyStorage Product repair and return informationPowerChoice modes Physical/electrical specificationsPowerChoiceTM power management DC power requirements AC power requirements1000GB drive Standard & SED model DC power requirements 500GB drive Standard & SED model DC power requirements Conducted noise immunity General DC power requirement notesPower sequencing TB model current profiles Current profilesGB model current profiles 1TB model drive in 3Gb operation Power dissipation1TB model drive in 6Gb operation 500GB model drive in 3Gb operation 500GB model drive in 6Gb operation Relative humidity Temperature a. OperatingEnvironmental limits Shock Effective altitude sea level a. OperatingShock and vibration Recommended mounting Vibration a. Operating-normal Air cleanlinessAcoustics Corrosive environmentSee Section Constellation.2 SAS Product Manual, Rev. H Mounting configuration dimensions Mechanical specificationsPurpose About FipsValidation Program Seagate Enterprise SEDExample of Fips tamper evidence labels Admin SP Controlled accessAbout self-encrypting drives Data encryptionRandom number generator RNG Authenticated firmware downloadDrive locking Data bandsSupported commands Power requirementsDrive error recovery procedures Defect and error managementDrive internal defects/errors SAS system errors Deferred Auto-Reallocation Background Media ScanMedia Pre-Scan Idle Read After Write Setting and determining the current Type LevelProtection Information PI Levels of PIIdentifying a Protection Information drive Drive orientation InstallationAir flow CoolingGrounding Drive mountingInterface requirements SAS featuresDual port support Supported commands Scsi commands supportedSupported commands Supported commands Supported commands Constellation.2 inquiry data Mode Sense dataInquiry data Page Block Descriptor 00 00 00 00 3a 38 60 30 00 00 00 00 00 00 02 Miscellaneous status Miscellaneous operating features and conditionsMiscellaneous features SAS physical interface Datum B Section C C Section a a Connector requirements Physical characteristicsElectrical description Pin descriptionsPower Signal characteristicsSAS transmitters and receivers Ready LED OutLED drive signal SAS-2 Specification ComplianceDifferential signals General interface characteristicsNumerics IndexKCC Msid Mtbf See also cooling Page Constellation.2 SAS Product Manual, Rev. H Page Americas Seagate Technology LLC
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