Seagate ST3300056SS (FDE), ST3146854LC, ST3146756SS (FDE), ST3146356SSIM, ST3450056SS (FDE) 51.87

Page 48

The drive firmware error recovery algorithms consists of 13 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 18 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 18: Read and write retry count maximum recovery times

Read retry count1

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

51.87

 

 

1

59.85

 

 

2

203.49

 

 

3

219.45

 

 

4

231.42

 

 

5

297.38

 

 

6

323.62

 

 

7

355.54

 

 

8

439.39

 

 

9

507.39

 

 

10

539.31

 

 

11

567.24

 

 

12

1,460.85

 

 

13 (default)

1,468.74

 

 

Write retry count1

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

23.94

 

 

1

35.91

 

 

2

55.86

 

 

3

67.83

 

 

4

119.79

 

 

5 (default)

147.72

 

 

[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 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.

44

Cheetah 15K.6 SAS Product Manual, Rev. B

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Contents ST3450856SS ST3300656SSST3146356SS Page Contents Defect and error management InstallationSeagate Technology support services Interface requirementsScope Model Number Full Disk Encryption FDECheetah 15K.6 SAS Product Manual, Rev. B Standards, compliance and reference documents StandardsElectromagnetic compatibility Electromagnetic susceptibilityCompliance European Union Restriction of Hazardous Substances RoHSReference documents Cheetah 15K.6 SAS Product Manual, Rev. B General description Standard features Media descriptionPerformance Factory-installed options ReliabilityFormatted capacities Programmable drive capacityCheetah 15K.6 SAS Product Manual, Rev. B Performance characteristics Internal drive characteristicsAccess time Seek timeFormat command execution time minutes General performance characteristicsStart/stop time 176 144 100Prefetch/multi-segmented cache control Cache operationCaching write data Prefetch operationReliability 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 MillisecondsReporting control Determining ratePredictive failures Thermal monitorTemperature Log Page 0Dh Parameter Code Description State of the drive prior to testingDrive Self Test DST DST failure definitionInvoking DST Short and extended testsShort test Function Code 001b Extended test Function Code 010bProduct warranty AbortShipping Product repair and return informationCheetah 15K.6 SAS Product Manual, Rev. B Physical/electrical specifications AC power requirementsDC power requirements ST3450856SS DC power requirementsST3450056SS FDE DC power requirements ST3300656SS DC power requirementsST3450056SS FDE Gbit mode Amps ST3300656SS Gbit mode AmpsST3300056SS FDE DC power requirements ST3146356SS DC power requirementsST3300056SS FDE Gbit mode Amps ST3146356SS Gbit mode AmpsST3146756SS FDE DC power requirements ST3146756SS FDE Gbit mode AmpsPower sequencing Conducted noise immunityCurrent profiles Typical 450GB current profiles Typical 146GB current profiles Power dissipation ST3450856SS modelST3450056SS FDE model ST3300656SS model ST3300056SS FDE model ST3146356SS model ST3146756SS FDE model in 3 Gbit operation Temperature Environmental limitsRelative humidity Effective altitude sea levelShock and vibration ShockPackage size Packaged/product weight Drop height Recommended mountingAir cleanliness VibrationAcoustics Corrosive environmentMechanical specifications Physical dimensions Cheetah 15K.6 SAS Product Manual, Rev. B Defect and error management Drive internal defects/errorsDrive error recovery procedures 51.87 SAS system errors Background Media ScanMedia Pre-Scan Deferred Auto-Reallocation Idle Read After WriteInstallation Drive orientationCooling Air flow Drive mounting GroundingCheetah 15K.6 SAS Product Manual, Rev. B SAS features Interface requirementsDual port support Scsi commands supported Commands supported by Cheetah 15K.6 SAS family drivesCommand name Command code Supported 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 Inquiry data Bytes Data hexMode Sense data 2.1 ST3450856SS/ST3450056SS Mode Sense data Mode Pages2.2 ST3300656SS/ST3300056SS Mode Sense data 2.3 ST3146356SS/ST3146756SS Mode Sense data Miscellaneous operating features and conditions Miscellaneous featuresMiscellaneous status SAS physical interfacePhysical interface Datum B Physical characteristics Connector requirementsPin Signal name Signal type Electrical descriptionPin descriptions SAS pin descriptionsSignal characteristics PowerSAS transmitters and receivers Ready LED OutLED drive signal Differential signalsGeneral interface characteristics Eye masks Eye masks overviewReceive eye mask Jitter tolerance masksAbsolute amplitude Normalized time in UIPeak-to SinusoidalJitter Frequency in kHzTransmitter signal characteristics Signal characteristica Units GbpsReceiver signal characteristics Signal characteristic Units GbpsMaximum allowable jitter Impedance specifications Receiver jitter toleranceCompliant jitter test pattern Cjtpat Impedance requirements Sheet 1Transmitter characteristics Impedance requirements Sheet 2Electrical TxRx connections = -5,437dB Shows the zero-length test load Receiver characteristics Cheetah 15K.6 SAS Product Manual, Rev. B Seagate Technology support services InternetPresales Support Technical SupportWarranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call Center Toll-free Direct dial Index NumericsIraw SAS See also cooling
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