Seagate ST3600857SS, ST3300457SS, ST3450657SS manual SAS system errors, Background Media Scan

Page 47

Table 17: 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.

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.

10.4Background 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. D

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Contents Standard models Self-Encrypting Drive models ST3600857SSST3450657SS ST3300457SSPage Contents Interface requirements Defect and error managementInstallation About Fips About self-encrypting drivesPower Cheetah 15K.7 SAS Product Manual, Rev. D Seagate Online Support and Services Seagate Technology support servicesScope Electromagnetic susceptibility Standards, compliance and reference documentsStandards Electromagnetic compatibilityEuropean Union Restriction of Hazardous Substances RoHS ComplianceReference documents General description Performance Standard featuresMedia description Programmable drive capacity Factory-installed optionsReliability Formatted capacitiesSeek time Performance characteristicsInternal drive characteristics Access timeStart/stop time Format command execution time minutesGeneral performance characteristics Cache operation Prefetch/multi-segmented cache controlPrefetch operation Caching write dataUnrecoverable Errors Reliability specificationsError rates Recoverable ErrorsPreventive maintenance Reliability and serviceSeek errors Interface errorsMilliseconds 4 S.M.A.R.TControlling S.M.A.R.T Performance impactThermal monitor Reporting controlDetermining rate Predictive failuresDST failure definition Temperature Log Page 0Dh Parameter Code DescriptionState of the drive prior to testing Drive Self Test DSTExtended test Function Code 010b Invoking DSTShort and extended tests Short test Function Code 001bProduct repair and return information Product warrantyAbort ShippingDC power requirements Physical/electrical specificationsAC power requirements Gbit mode Amps 600 GB DC power requirements450 GB DC power requirements 300 GB DC power requirements Current profiles Power sequencingConducted noise immunity Typical 600GB current profiles Typical 300GB current profiles Power dissipation 450GB model Environmental limits Temperature a. OperatingShock Relative humidityEffective altitude sea level a. Operating Shock and vibrationPackage size Packaged/product weight Drop height Recommended mounting Vibration a. Operating-normalRoHS compliance statement Air cleanlinessAcoustics Corrosive environmentUnits of Measure mm inches Mechanical specificationsLevel 2 security About FipsPurpose Data encryption Controlled accessAdmin SP About self-encrypting drivesData bands Authenticated firmware downloadRandom number generator RNG Drive lockingSupported commands Power requirementsDrive error recovery procedures Defect and error managementDrive internal defects/errors Page Background Media Scan SAS system errorsIdle Read After Write Media Pre-ScanDeferred Auto-Reallocation Cooling InstallationDrive orientation Grounding Drive mountingInterface requirements SAS featuresDual port support Scsi commands supportedCommands 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 Commands supported by Cheetah 15K.6 SAS family drives Cheetah 15K.7 inquiry data Bytes Data hex Inquiry dataMode Sense data Mode Pages 12.3.2.1 600GBmodel Mode Sense dataDEF CHG Mode Data Header Block Descriptor Mode Pages 12.3.2.2 450GB model Mode Sense dataDEF CHG Read Capacity Data Buffer C D E F Mode Pages 12.3.2.3 300GB model Mode Sense dataMiscellaneous features Miscellaneous operating features and conditionsSAS physical interface Miscellaneous statusDatum B Connector requirements Physical characteristicsSAS pin descriptions Electrical descriptionPin descriptions Ready LED Out Signal characteristicsPower SAS transmitters and receiversGeneral interface characteristics SAS-2 Specification complianceLED drive signal Differential signalsCheetah 15K.7 SAS Product Manual, Rev. D Numerics IndexPage SAS Smart
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