Seagate ST3146954FC, ST373554FC, ST336854FC manual Background Media Scan, Media Pre-Scan

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7.4Background Media Scan

7.4Background Media Scan

Background Media Scan (BGMS) is a self-initiated media scan. It performs sequential reads across the entire pack of the media while the drive is idle. In RAID arrays, BGMS allows hot spare drives to be scanned for defects prior to being put into service by the host system. On regular duty drives, if the host system makes use of the BGMS Log Page, it can avoid placing data in suspect locations on the media. Unrecovered error sites found during BGMS will be logged and recovered error sites will be logged or reallocated per ARRE/AWRE settings.

With BGMS, the host system can consume less power and system overhead by only checking BGMS status/ results rather than tying up the bus and consuming power in the process of host-initiated media scanning activ- ity.

Since the background scan functions are only done during idle periods, BGMS causes a negligible impact to system performance. Background media scan will begin after 500ms of idle time. Other features that normally use idle time to function will function normally because BGMS functions for bursts of 800ms and then sus- pends activity to allow other background functions to operate. Additionally, BGMS operates in segments of 400 block reads, checking for host commands upon completion of each of the block segments.

The BGMS function will complete any BGMS-initiated error recovery prior to returning to service host-initiated commands. Overhead associated with a return to host-servicing activity from BGMS only impacts the first com- mand that interrupted BGMS. This results in a typical delay of about 4 ms.

7.4.1Media Pre-Scan

Media Pre-Scan is an optional feature that allows the drive to handle unrecovered media errors that would oth- erwise have been found by the host system during critical data accesses early in the integration process at customer sites. This should reduce integration DPPM (defective parts per million) by identifying and repairing media errors that arose during shipping and handling. Media Pre-Scan replaces all host-initiated Write com- mands with Write-Verify commands when the drive is accessing areas of the media yet untouched by BGMS- initiated scanning activity.

The drive will attempt to run BGMS on the entire pack of the drive. This will result in increasingly large portions of the drive having been accessed, provided there is adequate idle time to allow BGMS to run. During the Pre- Scan period, all Write commands that are in areas not yet scanned by BGMS are converted to Write-Verify commands. To expedite the scan of the full pack and the subsequently exit from the Pre-Scan period, BGMS will begin immediately when the drive goes to idle during the Pre-Scan period, as opposed to waiting 500ms as is done under non-Pre-Scan conditions.

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Cheetah 15K.4 FC Product Manual, Rev. B

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Contents Cheetah 15K.4 FC ST3146954FC ST373554FC ST336854FCPage Cheetah 15K.4 FC March 07/15/05 Revision status summary sheetRev. A Rev. B DraftPage 5.0 Reliability specifications Contents4.0 Performance characteristics 6.0 Physical/electrical specifications7.0 Defect and error management 8.0 Installation9.0 Interface requirements 10.0 Seagate Technology support services Cheetah 15K.4 FC Product Manual, Rev. B List of Figures Page 1.0 Scope Figure 1. Cheetah 15K.4 FC family disc driveCheetah 15K.4 FC Product Manual, Rev. B 2.1.1 Electromagnetic compatibility 2.0 Applicable standards and reference documentation2.1 Standards 2.1.1.1 Electromagnetic susceptibilityAustralian C-Tick 2.1.2 Electromagnetic complianceElectromagnetic compliance for the European Union Korean MICSpecification for Acoustic Test Requirement and Procedures 2.2 Reference documentsFibre Channel Interface Manual Cheetah 15K.4 FC Product Manual, Rev. B 3.0 General description 3.1 Standard features 3.2 Media description3.5 Formatted capacities 3.3 Performance3.4 Reliability 3.5.1 Programmable drive capacity3.6 Factory-installed accessories 3.7 Factory-installed options3.8 User-installed accessories 4.2 Seek performance characteristics 4.0 Performance characteristics4.1 Internal drive characteristics 4.2.1 Access time4.3 Start/stop time 4.2.2 Format command execution time minutesGeneral performance characteristics 4.4 Prefetch/multi-segmented cache control4.5 Cache operation 4.5.1 Caching write data 4.5.2 Prefetch operationCheetah 15K.4 FC Product Manual, Rev. B Cheetah 15K.4 FC Product Manual, Rev. B 5.1.1 Recoverable Errors 5.0 Reliability specifications5.1 Error rates 5.1.2 Unrecoverable Errors5.1.4 Interface errors 5.2 Reliability and service5.1.3 Seek errors 5.2.2 Preventive maintenance5.2.3 Hot plugging the drive 5.2.4 S.M.A.R.TControlling S.M.A.R.T Maximum processing delay Fully-enabled delayPerformance impact On-line only delay5.2.6 Drive Self Test DST Parameter CodeDescription 5.2.6.1 DST failure definition5.2.6.2.2 Invoking DST 5.2.6.2.1 State of the drive prior to testing5.2.6.2 Implementation 5.2.6.2.3 Short and extended tests5.2.6.2.5 Abort 5.2.7 Product warranty5.2.6.2.4 Log page entries ShippingProduct repair and return information 6.0 Physical/electrical specifications 6.1 AC power requirements6.2 DC power requirements 3 See +12V current profile in Figure 6.2.1 Conducted noise immunity General DC power requirement notes6.2.2 Power sequencing 6.2.3 Current profilesFigure 2. Typical ST3146954FC drive, 2 Gbit, +12V current profile Figure 3. Typical ST3146954FC drive, 2 Gbit, +5V current profileFigure 4. Typical ST373554FC drive +12V current profile Figure 5. Typical ST373554FC drive +5V current profileFigure 6. Typical ST336854FC drive +12V current profile Figure 7. Typical ST336854FC drive +5V current profile6.3 Power dissipation ST3146954FCST373554FC Power wattsST336854FC 6.4 Environmental limits 6.4.1 Temperature a. Operating6.4.2 Relative humidity 6.4.3 Effective altitude sea level a. Operating 6.4.4 Shock and vibration6.4.4.1 Shock Drop height Packaged/product weightPackage size Figure 12. Recommended mounting6.4.6 Acoustics 6.4.5 Air cleanliness6.4.4.2 Vibration a. Operating-normal 6.4.7 Electromagnetic susceptibility6.5 Mechanical specifications Figure 13. Mounting configuration dimensions7.0 Defect and error management 7.1 Drive internal defects/errors7.2 Drive error recovery procedures Cheetah 15K.4 FC Product Manual, Rev. B 7.3 FC-AL system errors 7.4 Background Media Scan 7.4.1 Media Pre-Scan8.0 Installation 8.1 Drive ID/option selection8.2 LED connections Figure 15. LED indicator connectorFigure 14. Physical interface 8.2.1 J6 connector requirements 8.3 Drive orientation8.4 Cooling 8.5 Drive mounting 8.6 GroundingK x X = F 15lb = 67N 9.1 FC-AL features 9.1.1 Fibre Channel link service frames9.0 Interface requirements Fibre Channel SCSI FCP task management functions 9.1.2 Fibre Channel task management functions9.1.3 Fibre Channel task management responses Task name9.1.4 Fibre Channel port login NPort login PLOGI payloadBytes NPort Login Accept ACC payload 9.1.5 Fibre Channel port login accept9.1.6 Fibre Channel Process Login Process Login PLRI payloadProcess Login Accept ACC payload 9.1.7 Fibre Channel Process Login Accept9.1.8 Fibre Channel fabric login Fabric Login FLOGI payload9.1.9 Fibre Channel fabric accept login Fabric Login Accept ACC payload9.2 Dual port support 9.1.10 Fibre Channel Arbitrated Loop optionsCommand code 9.3 SCSI commands supportedTable 16 Supported commands Command nameTable 16 Supported commands continued Command name 3 Reference Mode Sense command 1Ah for mode pages supported 9.3.1 Inquiry data 9.3.2 Mode Sense data4. Changeable values CHG = Changeable bits indicates if default value is changeable3. Current values Definitions SAV = Current saved valueMODE SENSE 10 BYTE HEADER DATA Cheetah 15K.4 FC Product Manual, Rev. B Cheetah 15K.4 FC Product Manual, Rev. B Feature or condition 9.4 Miscellaneous operating features and conditionsMiscellaneous features Miscellaneous status9.5.1 Physical characteristics 9.5 FC-AL physical interface9.5.1.1 Physical description FC-AL SCA device connector dimensions 9.5.2 Connector requirementsFeatures Figure 20. J6 connector dimensions9.5.3 Electrical description 9.5.4 Pin descriptions9.5.5 FC-AL transmitters and receivers 9.5.6 Power9.5.7 Fault LED Out Figure 21. FC-AL transmitters and receivers9.5.10 Motor start controls 9.5.9 Enable port bypass signals9.5.8 Active LED Out Normal command activity9.5.11.1 Parallel Enclosure Services Interface ESI 9.5.11 SEL6 through SEL0 ID linesALPA SettingArbitrated loop physical address ALPA values SEL ID9.5.12 Device control codes 9.6 Signal characteristicsTTL input characteristics 9.6.19.6.4 FC Differential input 9.6.2 LED driver signals9.6.3 FC Differential output Bit Time Vout mv XMIT EyeVin mv Receive eye diagramEye diagram data values 941 ps 659 ps 376 psCheetah 15K.4 FC Product Manual, Rev. B Seagate Service Centers 10.0 Seagate Technology support servicesOnline services InternetWarranty Service Customer Service OperationsUSA/Canada/Latin America support services Seagate Service Centers Data Recovery ServicesFAX services-All Europe toll call European support servicesAfrica/Middle East support services Warranty ServiceAsia/Pacific support services Index NumericsDownload microcode with offsets and save mode 7 front panel 38 FS 49, 50, 52 function mounting 46 holes 46 orientations NN 49pin descriptions 66 PN 49 Self-Monitoring Analysis and Reporting Technology 9 SMP = 1 in Mode Select command 63 SO 49 LED driver 72 single-unit shipping pack kit 10 SMART 9UI 50, 51 unformatted Page Seagate Technology LLC