Seagate ST3146356SS Reporting control, Determining rate, Predictive failures, Thermal monitor

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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

Cheetah 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.

The thermal monitor system generates a warning code of 01-0B01 when the temperature exceeds the speci- fied limit in compliance with the SCSI standard. The drive temperature is reported in the FRU code field of mode sense data. You can use this information to determine if the warning is due to the temperature exceeding the drive threatening temperature or the user-specified temperature.

This feature is controlled by the Enable Warning (EWasc) bit, and the reporting mechanism is controlled by the Method of Reporting Informational Exceptions field (MRIE) on the Informational Exceptions Control (IEC) mode page (1Ch).

The current algorithm implements two temperature trip points. The first trip point is set at 68°C which is the maximum temperature limit according to the drive specification. The second trip point is user-selectable using the Log Select command. The reference temperature parameter in the temperature log page (see Table 1) can

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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 Defect and error management InstallationSeagate Technology support services 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 Standards, compliance and reference documents StandardsElectromagnetic compatibility Electromagnetic susceptibilityCompliance European Union Restriction of Hazardous Substances RoHSReference documents Cheetah 15K.6 SAS Product Manual, Rev. a General description Standard features Media descriptionPerformance Factory-installed accessories Options factory installedReliability Formatted capacitiesCheetah 15K.6 SAS Product Manual, Rev. a Performance characteristics Internal drive characteristicsAccess time Seek timeFormat command execution time minutes General performance characteristicsStart/stop time 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 Primary TemperatureReference Temperature Parameter Code DescriptionState of the drive prior to testing Invoking DSTShort and extended tests Short test Function Code 001bProduct warranty AbortShipping Product repair and return informationCheetah 15K.6 SAS Product Manual, Rev. a Physical/electrical specifications AC power requirementsDC power requirements ST3450856SS DC power requirementsST3300656SS DC power requirements ST3146356SS DC power requirementsST3300656SS Gbit mode Amps ST3146356SS Gbit mode AmpsGeneral DC power requirement notes Power sequencingConducted noise immunity 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 CURRENT/POWER vs Throughput SAS 3.0GB ST3146356SS in 3 Gbit operationRandom 8 Block Reads 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. a 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 flowDrive mounting GroundingCheetah 15K.6 SAS Product Manual, Rev. a 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 Mode Sense data Inquiry dataBytes Data hex Page 2.1 ST3450856SS Mode Sense data Mode Pages2.2 ST3300656SS Mode Sense data 2.3 ST3146356SS Mode Sense data Miscellaneous operating features and conditions Miscellaneous featuresSupported Feature or condition Miscellaneous statusSAS physical 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 Gbps m, n Deterministic jitterqImpedance 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. a Seagate Technology support services InternetPresales Support Technical SupportWarranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call Center Toll-free Direct dial Index NumericsPage SAS See also cooling
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