Seagate ST3300656SS, ST3146356SS, ST3450856SS manual 51.87

Page 46

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 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

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.

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

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Contents Cheetah 15K.6 SAS ST3450856SS ST3300656SS ST3146356SSPage Contents Seagate Technology support services Defect and error managementInstallation Interface requirementsList of Figures Cheetah 15K.6 SAS disk driveCheetah 15K.6 SAS Product Manual, Rev. a Scope Cheetah 15K.6 SAS disk driveCheetah 15K.6 SAS Product Manual, Rev. a Electromagnetic compatibility Standards, compliance and reference documentsStandards Electromagnetic susceptibilityCompliance European Union Restriction of Hazardous Substances RoHSReference documents Cheetah 15K.6 SAS Product Manual, Rev. a General description Media description Standard featuresPerformance Reliability Factory-installed accessoriesOptions factory installed Formatted capacitiesCheetah 15K.6 SAS Product Manual, Rev. a Access time Performance characteristicsInternal drive characteristics Seek timeGeneral performance characteristics Format command execution time minutesStart/stop time Prefetch/multi-segmented cache control Cache operationCaching write data Prefetch operationRecoverable Errors Reliability specificationsError rates Unrecoverable ErrorsInterface errors Reliability and serviceSeek errors Preventive maintenancePerformance impact 4 S.M.A.R.TControlling S.M.A.R.T MillisecondsPredictive failures Reporting controlDetermining rate Thermal monitorReference Temperature Temperature Log Page 0DhPrimary Temperature Parameter Code DescriptionShort and extended tests State of the drive prior to testingInvoking DST Short test Function Code 001bShipping Product warrantyAbort Product repair and return informationCheetah 15K.6 SAS Product Manual, Rev. a DC power requirements Physical/electrical specificationsAC power requirements ST3450856SS DC power requirementsST3300656SS Gbit mode Amps ST3300656SS DC power requirementsST3146356SS DC power requirements ST3146356SS Gbit mode AmpsConducted noise immunity General DC power requirement notesPower sequencing Current profilesTypical ST3450856SS current profiles Typical ST3300656SS current profiles Typical ST3146356SS current profiles Power dissipation ST3450856SS in 3 Gbit operationST3300656SS CURRENT/POWER vs Throughput SAS 3.0GB ST3300656SS in 3 Gbit operationST3146356SS in 3 Gbit operation ST3146356SS CURRENT/POWER vs Throughput SAS 3.0GBRandom 8 Block Reads Temperature Environmental limitsShock and vibration Relative humidityEffective altitude sea level ShockPackage size Packaged/product weight Drop height Recommended mountingAcoustics Air cleanlinessVibration Corrosive environmentMechanical specifications Physical dimensions Cheetah 15K.6 SAS Product Manual, Rev. a Drive internal defects/errors Defect and error managementDrive error recovery procedures 51.87 Background Media Scan SAS system errorsMedia Pre-Scan Deferred Auto-Reallocation Idle Read After WriteInstallation Drive orientationCooling Air flowDrive mounting GroundingCheetah 15K.6 SAS Product Manual, Rev. a SAS features Interface requirementsDual port support Commands supported by Cheetah 15K.6 SAS family drives Scsi commands supportedCommand 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 Mode Sense dataBytes Data hex Page 2.1 ST3450856SS Mode Sense data Mode Pages2.2 ST3300656SS Mode Sense data 2.3 ST3146356SS Mode Sense data Supported Feature or condition Miscellaneous operating features and conditionsMiscellaneous features Miscellaneous statusSAS physical interface Datum B Physical characteristics Connector requirementsPin descriptions Pin Signal name Signal typeElectrical description SAS pin descriptionsSAS transmitters and receivers Signal characteristicsPower Ready LED OutGeneral interface characteristics LED drive signalDifferential signals Eye masks Eye masks overviewAbsolute amplitude Receive eye maskJitter tolerance masks Normalized time in UIJitter Peak-toSinusoidal Frequency in kHzTransmitter signal characteristics Signal characteristica Units GbpsMaximum allowable jitter Receiver signal characteristicsSignal characteristic Units Gbps Gbps m, n Deterministic jitterqCompliant jitter test pattern Cjtpat Impedance specificationsReceiver jitter tolerance Impedance requirements Sheet 1Impedance requirements Sheet 2 Transmitter characteristicsElectrical TxRx connections = -5,437dB Shows the zero-length test load Receiver characteristics Cheetah 15K.6 SAS Product Manual, Rev. a Presales Support Seagate Technology support servicesInternet Technical SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Index NumericsPage SAS See also cooling
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