Seagate ST3450857SS manual 4 S.M.A.R.T, Controlling S.M.A.R.T, Performance impact, Milliseconds

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5.2.4S.M.A.R.T.

S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a failure to allow you to back up the data before an actual failure occurs.

Note. The drive’s firmware monitors specific attributes for degradation over time but can’t predict instanta- neous drive failures.

Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating per- formance of the drive and the thresholds are optimized to minimize “false” and “failed” predictions.

Controlling S.M.A.R.T.

The operating mode of S.M.A.R.T. is controlled by the DEXCPT and PERF bits on the Informational Exceptions Control mode page (1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEX- CPT bit disables all S.M.A.R.T. functions. When enabled, S.M.A.R.T. collects on-line data as the drive performs normal read and write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode Only” and will not perform off-line functions.

You can measure off-line attributes and force the drive to save the data by using the Rezero Unit command. Forcing S.M.A.R.T. resets the timer so that the next scheduled interrupt is in two hours.

You can interrogate the drive through the host to determine the time remaining before the next scheduled mea- surement and data logging process occurs. To accomplish this, issue a Log Sense command to log page 0x3E. This allows you to control when S.M.A.R.T. interruptions occur. Forcing S.M.A.R.T. with the RTZ command resets the timer.

Performance impact

S.M.A.R.T. attribute data is saved to the disk so that the events that caused a predictive failure can be recre- ated. The drive measures and saves parameters once every two hours subject to an idle period on the drive interfaces. The process of measuring off-line attribute data and saving data to the disk is uninterruptable. The maximum on-line only processing delay is summarized below:

Maximum processing delay
	On-line only delay	Fully-enabled delay
	DEXCPT = 0, PERF = 1	DEXCPT = 0, PERF = 0
S.M.A.R.T. delay times	42 milliseconds	163 milliseconds

14	Cheetah 15K.7 SAS Product Manual, Rev. A

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Contents Cheetah 15K.7 SAS Standard models Self-Encrypting Drive modelsPage Contents Defect and error management InstallationAbout self-encrypting drives Interface requirementsSeagate Technology support services Cheetah 15K.7 SAS Product Manual, Rev. a Scope Model Number Capacity Self-Encrypting Drive SEDStandards, compliance and reference documents StandardsElectromagnetic compatibility Electromagnetic susceptibilityCompliance European Union Restriction of Hazardous Substances RoHSReference documents General description Performance Standard featuresMedia description Factory-installed options ReliabilityFormatted capacities Programmable drive capacityPerformance characteristics Internal drive characteristicsAccess time Seek timeStart/stop time Format command execution time minutesGeneral performance characteristics Prefetch/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 informationDC power requirements Physical/electrical specificationsAC power requirements 600 GB DC power requirements ST3600057SS ST3600957SS Gbit mode Amps450 GB DC power requirements ST3450857SS ST3450757SS Gbit mode Amps300 GB DC power requirements ST3300657SS ST3300557SS Gbit mode AmpsCurrent profiles Power sequencingConducted noise immunity Typical 600GB current profiles Typical 300GB current profiles Power dissipation ST3600057SS modelST3450857SS model ST3300657SS model TemperatureEnvironmental limits Relative humidity Effective altitude sea levelShock and vibration ShockPackage size Packaged/product weight Drop height Vibration Recommended mountingAir cleanliness AcousticsCorrosive environment RoHS compliance statementMechanical specifications Physical dimensionsControlled access Admin SPAbout self-encrypting drives Data encryptionAuthenticated firmware download Random number generator RNGDrive locking Data bandsPower requirements Supported commandsDrive error recovery procedures Defect and error managementDrive internal defects/errors Page SAS system errors Background Media ScanIdle Read After Write Media Pre-ScanDeferred Auto-Reallocation Cooling InstallationDrive orientation Drive mounting GroundingSAS features Interface requirementsScsi commands supported Commands supported by Cheetah 15K.6 SAS family drivesCommand name Command code Supported Dual port supportCommands 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 Cheetah 15K.7 inquiry data Bytes Data hexMode Sense data 10.3.2.1 ST3600057SS and ST3600957SS Mode Sense data Mode PagesDEF CHG 10.3.2.2 ST3450857SS and ST3450757SS Mode Sense data Mode Data Header Block Descriptor Mode PagesDEF CHG Read Capacity Data Buffer C D E F 10.3.2.3 ST3300657SS and ST3300557SS Mode Sense data Mode PagesMiscellaneous operating features and conditions Miscellaneous featuresSupported Feature or condition Miscellaneous statusSAS physical interface Physical interfaceDatum B Physical characteristics Connector requirementsPin Signal name Signal type Electrical descriptionPin descriptions SAS pin descriptionsSignal characteristics PowerSAS transmitters and receivers Ready LED OutSAS-2 Specification compliance LED drive signalDifferential signals General interface characteristicsTechnical Support Seagate Technology support servicesPresales Support Data Recovery Services Call CenterToll-freeDirect dialFAX Warranty ServiceData Recovery Services Authorized Service Centers Cheetah 15K.7 SAS Product Manual, Rev. a Index NumericsPage SAS Smart

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