Seagate ST3450757SS, ST3300657SS, ST3300557SS, ST3450857SS SAS system errors, Background Media Scan

Page 45

Table 16: Read and write retry count maximum recovery times [1]

Read retry

Maximum recovery time per LBA

count

(cumulative, msec)

 

 

0

51.87

 

 

1

59.85

 

 

2

203.49

 

 

3

231.42

 

 

4

295.26

 

 

5

327.18

 

 

6

359.10

 

 

7

446.88

 

 

8

538.65

 

 

9

570.57

 

 

10

598.50

 

 

11 (default)

1,534.97

 

 

[1]These values are subject to change.

Write retry

Maximum recovery time per LBA

count

(cumulative, msec)

 

 

0

23.94

 

 

1

35.91

 

 

2

39.9

 

 

3

51.87

 

 

4

79.8

 

 

5 (default)

107.73

 

 

Setting these retry counts to a value below the default setting could result in degradation of the unrecov- ered error rate which may exceed the value given in this product manual. A setting of zero (0) will result in the drive not performing error recovery.

For example, suppose the read/write recovery page has the RC bit set to 0, read retry count set to 4, and the recovery time limit field (Mode Sense page 01, bytes 10 and 11) set to FF FF hex (maximum). A four LBA Read command is allowed to take up to 253.11 msec recovery time for each of the four LBAs in the command. If the recovery time limit is set to 00 C8 hex (200 msec decimal) a four LBA read command is allowed to take up to 200 msec for all error recovery within that command. The use of the Recovery Time Limit field allows finer granularity on control of the time spent in error recovery. The recovery time limit only starts counting when the drive is executing error recovery and it restarts on each command. There- fore, each command’s total recovery time is subject to the recovery time limit. Note: A recovery time limit of 0 will use the drive’s default value of FF FF. Minimum recovery time limit is achieved by setting the Recovery Time Limit field to 00 01.

8.3SAS 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.

8.4Background Media Scan

Background Media Scan (BMS) is a self-initiated media scan. BMS is defined in the T10 document SPC-4 available from the T10 committee. BMS performs sequential reads across the entire pack of the media while the drive is idle. In RAID arrays, BMS allows hot spare drives to be scanned for defects prior to being put into service by the host system. On regular duty drives, if the host system makes use of the BMS Log Page, it can avoid placing data in suspect locations on the media. Unreadable and recovered error sites will be logged or reallocated per ARRE/AWRE settings.

Cheetah 15K.7 SAS Product Manual, Rev. A

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Contents Standard models Self-Encrypting Drive models Cheetah 15K.7 SASPage Contents Installation Defect and error managementAbout self-encrypting drives Interface requirementsSeagate Technology support services Cheetah 15K.7 SAS Product Manual, Rev. a Model Number Capacity Self-Encrypting Drive SED ScopeStandards Standards, compliance and reference documentsElectromagnetic compatibility Electromagnetic susceptibilityEuropean Union Restriction of Hazardous Substances RoHS ComplianceReference documents General description Standard features Media descriptionPerformance Reliability Factory-installed optionsFormatted capacities Programmable drive capacityInternal drive characteristics Performance characteristicsAccess time Seek timeFormat command execution time minutes General performance characteristicsStart/stop time Cache 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 MillisecondsDetermining rate Reporting controlPredictive failures Thermal monitorState of the drive prior to testing Temperature Log Page 0Dh Parameter Code DescriptionDrive Self Test DST DST failure definitionShort and extended tests Invoking DSTShort test Function Code 001b Extended test Function Code 010bAbort Product warrantyShipping Product repair and return informationPhysical/electrical specifications AC power requirementsDC power requirements ST3600057SS ST3600957SS Gbit mode Amps 600 GB DC power requirementsST3450857SS ST3450757SS Gbit mode Amps 450 GB DC power requirementsST3300657SS ST3300557SS Gbit mode Amps 300 GB DC power requirementsPower sequencing Conducted noise immunityCurrent profiles Typical 600GB current profiles Typical 300GB current profiles ST3600057SS model Power dissipationST3450857SS model Temperature Environmental limitsST3300657SS model Effective altitude sea level Relative humidityShock and vibration ShockPackage size Packaged/product weight Drop height Recommended mounting VibrationAcoustics Air cleanlinessCorrosive environment RoHS compliance statementPhysical dimensions Mechanical specificationsAdmin SP Controlled accessAbout self-encrypting drives Data encryptionRandom number generator RNG Authenticated firmware downloadDrive locking Data bandsSupported commands Power requirementsDefect and error management Drive internal defects/errorsDrive error recovery procedures Page Background Media Scan SAS system errorsMedia Pre-Scan Deferred Auto-ReallocationIdle Read After Write Installation Drive orientationCooling Grounding Drive mountingInterface requirements SAS featuresCommands supported by Cheetah 15K.6 SAS family drives Scsi commands supportedCommand name Command code Supported Dual port supportCommands supported by Cheetah 15K.6 SAS family drives Commands supported by Cheetah 15K.6 SAS family drives Commands supported by Cheetah 15K.6 SAS family drives Cheetah 15K.7 inquiry data Bytes Data hex Inquiry dataMode Sense data Mode Pages 10.3.2.1 ST3600057SS and ST3600957SS Mode Sense dataDEF CHG Mode Data Header Block Descriptor Mode Pages 10.3.2.2 ST3450857SS and ST3450757SS Mode Sense dataDEF CHG Read Capacity Data Buffer C D E F Mode Pages 10.3.2.3 ST3300657SS and ST3300557SS Mode Sense dataMiscellaneous features Miscellaneous operating features and conditionsSupported Feature or condition Miscellaneous statusPhysical interface SAS physical interfaceDatum B Connector requirements Physical characteristicsElectrical description Pin Signal name Signal typePin descriptions SAS pin descriptionsPower Signal characteristicsSAS transmitters and receivers Ready LED OutLED drive signal SAS-2 Specification complianceDifferential signals General interface characteristicsSeagate Technology support services Presales SupportTechnical Support Warranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call CenterToll-freeDirect dialFAX Cheetah 15K.7 SAS Product Manual, Rev. a Numerics IndexPage SAS Smart
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