Seagate ST3450802SS, ST3600002SS manual 77.81

Page 36

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 14 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 14: Read and write retry count maximum recovery times

Read retry count1

Maximum recovery time per

LBA (cumulative, ms)

 

 

 

 

0

77.81

 

 

1

89.78

 

 

2

305.24

 

 

3

347.13

 

 

4

442.89

 

 

5

490.77

 

 

6

538.65

 

 

7

670.32

 

 

8

807.98

 

 

9

855.86

 

 

10

897.75

 

 

11 (default)

2370.04

 

 

Write retry count1

Maximum recovery time per

LBA (cumulative, ms)

 

 

0

35.91

 

 

1

53.865

 

 

2

83.79

 

 

3

101.745

 

 

4

179.655

 

 

5 (default)

221.55

 

 

[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 442.89 ms recovery time for each of the four LBAs in the command. If the recovery time limit is set to 00 C8 hex (200 ms decimal) a four LBA read command is allowed to take up to 200 ms 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. Therefore, 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.

32

Cheetah NS 10K.2 SAS Product Manual, Rev. F

Page 35 Page 37
Image 36
Page 35 Page 37
Contents Cheetah NS 10K.2 SAS ST3600002SS ST3450802SSPage Contents Defect and error management InstallationInterface requirements Seagate Technology support services Seagate Online Support and ServicesScope Standards, compliance and reference documents StandardsElectromagnetic compatibility Electromagnetic susceptibilityCompliance Reference documents General description Standard features Media descriptionPerformance ReliabilityFactory-installed options Formatted capacitiesProgrammable drive capacity Performance characteristics Internal drive characteristicsAccess time Seek performanceFormat command execution time minutes General performance characteristicsStart/stop time Prefetch/multi-segmented cache control Cache operationCaching write data Prefetch operation Reliability specifications Error ratesRecoverable Errors Unrecoverable ErrorsReliability and service Interface errorsPreventive maintenance Hot plugging the drive4 S.M.A.R.T Controlling S.M.A.R.TPerformance impact Reporting controlTemperature Log Page 0Dh Parameter Code Description Predictive failuresThermal monitor Drive Self Test DSTDST failure definition ImplementationProduct warranty Short test Function Code 001bExtended test Function Code 010b Shipping Physical/electrical specifications AC power requirementsDC power requirements ST3600002SS DC power requirementsST3450802SS DC power requirements General DC power requirement notesPower sequencing Conducted noise immunityCurrent profiles Typical ST3600002SS drive +5V and +12V current profiles Power dissipation ST3600002SSST3450802SS Temperature a. Operating Environmental limitsRelative humidity Effective altitude sea level a. OperatingShock and vibration ShockRecommended mounting Air cleanliness Vibration a. Operating-normalAcoustics Corrosive environmentChina Restriction of Hazardous Substances RoHS Directive Mechanical specifications Physical dimensionsDefect and error management Drive internal defects/errorsDrive error recovery procedures 77.81 SAS system errors Background Media ScanMedia Pre-Scan Deferred Auto-ReallocationIdle Read After Write Installation Drive orientationCooling Air flowDrive mounting GroundingSAS features Interface requirementsDual port support Scsi commands supported Commands supported by Cheetah NS 10K.2 SAS family drivesCommands supported by Cheetah NS 10K.2 SAS family drives Commands supported by Cheetah NS 10K.2 SAS family drives Commands supported by Cheetah NS 10K.2 SAS family drives Inquiry data 10.3.2Mode Sense dataPage 10.3.2.1 ST3600002SS Mode Sense data Mode Pages10.3.2.2 ST3450802SS Mode Sense data Miscellaneous operating features and conditions Miscellaneous featuresMiscellaneous status SAS physical interface Datum B Physical characteristics Connector requirementsElectrical description Pin descriptionsSAS pin descriptions Signal characteristics PowerSAS transmitters and receivers Ready LED OutLED drive signal Differential signalsGeneral interface characteristics 10.5.2.1 Eye masks 10.5.2.1.1 Eye masks overviewReceive eye mask 2OP 0, 5 xadditional sinusoidal jitter X 1OP Transmitter signal characteristics Receiver signal characteristics Maximum allowable jitterCompliant jitter test pattern Cjtpat Impedance requirements Sheet 1Impedance requirements Sheet 2 Electrical TxRx connections= -5, 437dB Shows the zero-length test load SAS-2 Specification compliance Receiver characteristicsAdditional information Cheetah NS 10K.2 SAS Product Manual, Rev. F Index Page SAS See also cooling Page Seagate Technology LLC Americas
Related manuals
Manual 74 pages 45.81 Kb
Top Page Image Contents