Seagate ST3750630SS, ST31000640SS, ST3500620SS manual 108.29

Page 40

The drive firmware error recovery algorithms consists of 11 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 5 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 5: Read and write retry count maximum recovery times

Read retry count1

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

108.29

 

 

1

124.95

 

 

2

424.83

 

 

3

483.14

 

 

4

583.78

 

 

5

646.11

 

 

6

712.75

 

 

7

870.69

 

 

8

964.71

 

 

9

1031.35

 

 

10

1089.66

 

 

11 (default)

2369.00

 

 

Write retry count1

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

49.98

 

 

1

74.97

 

 

2

116.62

 

 

3

141.61

 

 

4

250.08

 

 

5 (default)

308.39

 

 

[1]These values are subject to change.

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 297.38 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.

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Barracuda ES.2 SAS Product Manual, Rev. E

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Contents Barracuda ES.2 SAS ST31000640SS ST3750630SS ST3500620SSPage Contents Defect and error management InstallationSeagate Technology support services Interface requirementsScope Barracuda ES.2 SAS Product Manual, Rev. E Standards, compliance and reference documents StandardsElectromagnetic compatibility Electromagnetic susceptibilityCompliance Reference documents Barracuda ES.2 SAS Product Manual, Rev. E General description Barracuda ES.2 drive illustrationStandard features Media descriptionPerformance ReliabilityFormatted capacities Factory-installed optionsProgrammable drive capacity Barracuda ES.2 SAS Product Manual, Rev. E Performance characteristics Internal drive characteristicsAccess time Seek performanceGeneral performance characteristics Format command execution time minutesStart/stop time Cache operation Prefetch/multi-segmented cache controlCaching write data Prefetch operation Reliability specifications Error ratesRecoverable Errors Unrecoverable ErrorsReliability and service Seek errorsInterface errors Preventive maintenance4 S.M.A.R.T Controlling S.M.A.R.TPerformance impact Reporting controlPredictive failures Temperature Log Page 0DhThermal monitor State of the drive prior to testing DST failure definitionImplementation Invoking DSTProduct warranty Short test Function Code 001bExtended test Function Code 010b Log page entriesShipping Product repair and return informationBarracuda ES.2 SAS Product Manual, Rev. E Physical/electrical specifications AC power requirementsDC power requirements ST31000640SS DC power requirementsST3750630SS DC power requirements ST3500620SS DC power requirementsGeneral DC power requirement notes Power sequencingConducted noise immunity Current profilesTypical ST31000640SS drive +5V and +12V current profiles Power dissipation Typical ST3500620SS drive +5V and +12V current profilesBarracuda ES.2 SAS Product Manual, Rev. E Temperature a. Operating Environmental limitsRelative humidity Effective altitude sea level a. OperatingShock and vibration ShockPackage size Packaged/product weight Drop height Air cleanliness Vibration a. Operating-normalAcoustics Corrosive environment X表示该部件（于同类物品程度上）所含的危险和有毒物质超出中国RoHS MCV标准所定义的门槛值。 Mechanical specifications Physical dimensionsDrive internal defects/errors Defect and error managementDrive error recovery procedures 108.29 Background Media Scan SAS system errorsMedia Pre-Scan Deferred Auto-Reallocation Idle Read After WriteInstallation Drive orientationCooling Air flowDrive mounting GroundingBarracuda ES.2 SAS Product Manual, Rev. E SAS features Interface requirementsDual port support Scsi commands supported Commands supported by Barracuda ES.2 SAS family drivesCommands supported by Barracuda ES.2 SAS family drives Commands supported by Barracuda ES.2 SAS family drives Commands supported by Barracuda ES.2 SAS family drives Mode Sense data Inquiry dataPage 2.1 ST31000640SS Mode Sense data Mode Pages2.2 ST3750630SS Mode Sense data 2.3 ST3500620SS Mode Sense data Miscellaneous features Miscellaneous operating features and conditionsMiscellaneous status SAS physical interface Datum B Physical characteristics Connector requirementsPin descriptions Electrical descriptionSAS pin descriptions Signal characteristics PowerSAS transmitters and receivers Ready LED OutLED drive signal Differential signalsGeneral interface characteristics Eye masks Eye masks overviewReceive eye mask Jitter tolerance masksPeak-to SinusoidalJitter Frequency in kHzTransmitter signal characteristics Receiver signal characteristics Maximum allowable jitterImpedance specifications Receiver jitter toleranceCompliant jitter test pattern Cjtpat Impedance requirements Sheet 1Impedance requirements Sheet 2 Transmitter characteristicsElectrical TxRx connections = -5, 437dB Shows the zero-length test load Receiver characteristics Barracuda ES.2 SAS Product Manual, Rev. E Seagate Technology support services InternetPresales Support Technical SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Index Page SAS See also cooling Page Seagate Technology LLC
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