Seagate ST9300553SS 4 S.M.A.R.T, Controlling S.M.A.R.T, Performance impact, Reporting control

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6.2.4S.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 one hour.

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 hour subject to an idle period on the drive inter- faces. 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

 

Fully-enabled delay

 

DEXCPT = 0

S.M.A.R.T. delay times

70 milliseconds

Reporting control

Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). Subject to the reporting method. For example, if the MRIE is set to one, the firmware will issue to the host an 01-5D00 sense code. The FRU field contains the type of predictive failure that occurred. The error code is preserved through bus resets and power cycles.

Determining rate

S.M.A.R.T. monitors the rate at which errors occur and signals a predictive failure if the rate of degraded errors increases to an unacceptable level. To determine rate, error events are logged and compared to the number of total operations for a given attribute. The interval defines the number of operations over which to measure the rate. The counter that keeps track of the current number of operations is referred to as the Interval Counter.

S.M.A.R.T. measures error rates. All errors for each monitored attribute are recorded. A counter keeps track of the number of errors for the current interval. This counter is referred to as the Failure Counter.

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Contents ST9300453SS ST9146653SS ST9300653SSST9300553SS ST9146853SSST9146753SSStandard Models Self-Encrypting Drive Models SED FIPS140-2 ModelsPage Contents Installation Defect and error managementAbout Fips About self-encrypting drives Interface requirementsPage Savvio 15K.3 SAS Product Manual, Rev. a List of Figures Page Seagate Online Support and Services Seagate Technology support servicesScope Standards Applicable standards and reference documentationElectromagnetic compatibility Electromagnetic susceptibilityElectromagnetic compliance for the European Union Electromagnetic complianceAustralian C-Tick Korean KCCEuropean Union Restriction of Hazardous Substances RoHS Reference documents Scsi Commands Reference Manual SAS Interface ManualGeneral description Media description Standard featuresReliability PerformanceFormatted capacities Programmable drive capacity Factory installed optionsInternal drive characteristics Performance characteristicsSeek performance characteristics Access timeGeneral performance characteristics Format command execution timeStart/stop time Cache operation Prefetch/multi-segmented cache controlPrefetch operation Caching write dataError rates Reliability specificationsRecoverable Errors Unrecoverable ErrorsSeek errors Reliability and serviceInterface errors Preventive maintenance4 S.M.A.R.T Maximum processing delayControlling S.M.A.R.T Performance impactPredictive failures Temperature Log Page 0Dh Parameter Code DescriptionThermal monitor Drive Self Test DST State of the drive prior to testingDST failure definition ImplementationShort test Function Code 001b Short and extended testsExtended test Function Code 010b Log page entriesShipping Product warrantyProduct repair and return information StoragePowerChoiceTM power management Physical/electrical specificationsPowerChoice modes DC power requirements AC power requirementsRegulation 300GB models DC power requirements146GB models DC power requirements Power sequencing General DC power requirement notesConducted noise immunity Current profile for 300GB models Current profilesCurrent profile for 146GB models 300GB models in 6Gb operation Power dissipation300GB models in 3Gb operation 146GB models in 3Gb operation 146GB models in 6Gb operationEnvironmental limits Temperature a. OperatingRelative humidity Shock and vibration Effective altitude sea level a. OperatingShock Recommended mounting Vibration a. Operating-normalCorrosive environment Air cleanlinessAcoustics Dimensions Mechanical specificationsPurpose About FipsLevel 2 security Admin SP Controlled accessAbout self-encrypting drives Data encryptionRandom number generator RNG Default passwordDrive locking Data bandsPower requirements Authenticated firmware downloadSupported commands Cryptographic eraseDrive internal defects/errors Defect and error managementDrive error recovery procedures Background Media Scan SAS system errorsDeferred Auto-Reallocation Media Pre-ScanIdle Read After Write Protection Information PI Setting and determining the current Type LevelLevels of PI Identifying a Protection Information driveDrive orientation InstallationAir flow CoolingGrounding Drive mountingInterface requirements SAS featuresSupported commands Scsi commands supportedDual port support Supported commands Supported commands Supported commands Inquiry data Mode Sense dataSavvio inquiry data Page Mode Data Header Mode Data Header Miscellaneous features Miscellaneous operating features and conditionsMiscellaneous status SAS physical interface Datum B Section C C Section a a Connector requirements Physical characteristicsElectrical description Pin descriptionsPower Signal characteristicsSAS transmitters and receivers Ready LED OutLED drive signal SAS-2 Specification complianceDifferential signals General interface characteristicsNumerics IndexPage Msid Mtbf See also cooling Page Savvio 15K.3 SAS Product Manual, Rev. a
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