Seagate ST973451FC Performance impact, Reporting control, Determining rate, Predictive failures

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Performance impact

S.M.A.R.T. attribute data is saved to the disc 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 FC-AL bus. The process of measuring off-line attribute data and saving data to the disc is uninterruptable. The maxi- mum 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

50 milliseconds

300 milliseconds

Reporting control

Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). Subject to the reporting method, the firmware will issue to the host an 01-5Dxx sense code. 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.

Error rate is the number of errors per operation. The algorithm that S.M.A.R.T. uses to record rates of error is to set thresholds for the number of errors and their interval. If the number of errors exceeds the threshold before the interval expires, the error rate is considered to be unacceptable. If the number of errors does not exceed the threshold before the interval expires, the error rate is considered to be acceptable. In either case, the inter- val and failure counters are reset and the process starts over.

Predictive failures

S.M.A.R.T. signals predictive failures when the drive is performing unacceptably for a period of time. The firm- ware keeps a running count of the number of times the error rate for each attribute is unacceptable. To accom- plish this, a counter is incremented each time the error rate is unacceptable and decremented (not to exceed zero) whenever the error rate is acceptable. If the counter continually increments such that it reaches the pre- dictive threshold, a predictive failure is signaled. This counter is referred to as the Failure History Counter. There is a separate Failure History Counter for each attribute.

5.2.5Thermal monitor

Savvio drives implement a temperature warning system which:

1.Signals the host if the temperature exceeds a value which would threaten the drive.

2.Signals the host if the temperature exceeds a user-specified value.

3.Saves a S.M.A.R.T. data frame on the drive which exceeds the threatening temperature value.

A temperature sensor monitors the drive temperature and issues a warning over the interface when the tem- perature exceeds a set threshold. The temperature is measured at power-up and then at ten-minute intervals after power-up.

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Savvio 15K.1 FC Product Manual, Rev. B

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Contents Savvio 15K.1 FC ST973451FC ST936751FCPage Contents Installation Physical/electrical specificationsDefect and error management Interface requirementsSeagate Technology support services Savvio 15K.1 FC Product Manual, Rev. B List of Figures Page Scope Savvio 15K.1 family disc driveSavvio 15K.1 FC Product Manual, Rev. B Electromagnetic compatibility Applicable standards and reference documentationStandards Electromagnetic susceptibilityEuropean Union Restriction of Hazardous Substances RoHS Reference documents Ncits TR-19Savvio 15K.1 FC Product Manual, Rev. B General description Standard features Reliability Media descriptionPerformance Formatted capacitiesProgrammable drive capacity Factory-installed accessoriesOptions Seek performance characteristics Performance characteristicsInternal drive characteristics Access timeStart/stop time Format command execution timeGeneral performance characteristics Caching write data Prefetch/multi-segmented cache controlCache operation Prefetch operation Recoverable Errors Reliability specificationsError rates Seek errors Reliability and serviceUnrecoverable Errors Interface errorsControlling S.M.A.R.T Hot plugging the drive4 S.M.A.R.T Determining rate Performance impactReporting control Predictive failuresDrive Self Test DST Temperature Log Page 0DhParameter Code Description DST failure definitionInvoking DST State of the drive prior to testingImplementation Short and extended testsAbort Product warrantyLog page entries ShippingProduct repair and return information DC power requirements Physical/electrical specificationsAC power requirements General DC power requirement notes Current profiles Power sequencingConducted noise immunity +5V +12VTypical ST936751FC drive +12V and +5V current profiles ST973451FC Power dissipationCURRENT/POWER vs Throughput FC 1GB Random 8 Block Reads CURRENT/POWER vs Throughput FC 4GB Random 8 Block Reads FC CURRENT/POWER vs Throughput FC 1GB Random 8 Block Reads ST936751FCEnvironmental limits TemperatureFC CURRENT/POWER vs Throughput FC 4GB Random 8 Block Reads Shock and vibration Relative humidityEffective altitude sea level ShockPackage size Packaged/product weight Drop height Recommended mounting Corrosive environment Air cleanlinessVibration Acoustics Mechanical specifications Drive dimensions inchesDrive error recovery procedures Defect and error managementDrive internal defects/errors FC-AL system errors Deferred Auto-Reallocation Background Media ScanMedia Pre-Scan Idle Read After Write Cooling InstallationDrive orientation Drive mounting GroundingLink services supported Type of frame FC-AL featuresFibre Channel link service frames Interface requirementsFibre Channel Scsi FCP task management functions Fibre Channel task management functionsFibre Channel task management responses Task name SupportedFibre Channel port login NPort login Plogi payload BytesNPort Login Accept ACC payload Bytes Fibre Channel port login acceptFibre Channel Process Login Process Login Plri payloadProcess Login Accept ACC payload Bytes Fibre Channel Process Login AcceptFibre Channel fabric login Fabric Login Flogi payload BytesFibre Channel fabric accept login Fabric Login Accept ACC payload BytesFC-AL options supported Dual port supportFibre Channel Arbitrated Loop options Option SupportedScsi commands supported Supported commands Command code Command nameDisconnect/reconnect control page 02h Savvio 15K.1 FC Product Manual, Rev. B LBdata Supported commands Command code Supported 4 Command name Inquiry data Savvio inquiry data Bytes Data hexSupported Feature or condition Miscellaneous operating features and conditionsMiscellaneous features Miscellaneous statusPhysical description Physical characteristicsFC-AL physical interface Electrical description Connector requirementsPart description Positions Part number Features Pin descriptions FC-SCA pin descriptions Pin Signal name Signal typePin Signal name Signal type FC-AL transmitters and receivers PowerFault LED Out Motor start controls Enable port bypass signalsActive LED Out Parallel Enclosure Services Interface ESI 11 SEL6 through SEL0 ID linesHex Dec SettingArbitrated loop physical address Alpa values Device control codes Signal characteristicsTTL input characteristics Differential Pecl output Differential Pecl inputSavvio 15K.1 FC Product Manual, Rev. B Presales Support Seagate Technology support servicesInternet Technical SupportData Recovery Services Call Center Toll-free Direct dial Warranty ServiceData Recovery Services Authorized Service Centers Index NumericsFAN Page Plogi SEL ID See also cooling