Seagate ST3450856FC manual Media Pre-Scan, Deferred Auto-Reallocation, Idle Read After Write

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avoid placing data in suspect locations on the media. Unreadable and recovered error sites will be logged or reallocated per ARRE/AWRE settings.

With BMS, the host system can consume less power and system overhead by only checking BMS status and 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, BMS causes a negligible impact to sys- tem performance. The first BMS scan for a newly manufactured drive is performed as quickly as possible to verify the media and protect data by setting the “Start time after idle” to 5ms, all subsequent scans begin after 500ms of idle time. Other features that normally use idle time to function will function normally because BMS functions for bursts of 800ms and then suspends activity for 100ms to allow other background functions to operate.

BMS interrupts immediately to service host commands from the interface bus while performing reads. BMS will complete any BMS-initiated error recovery prior to returning to service host-initiated commands. Overhead associated with a return to host-servicing activity from BMS only impacts the first command that interrupted BMS, this results in a typical delay of about 1 ms.

7.5Media Pre-Scan

Media Pre-Scan is a feature that allows the drive to repair media errors that would otherwise have been found by the host system during critical data accesses early in the drive’s life. The default setting for Media Pre-Scan is enabled on standard products. Media Pre-Scan checks each write command to determine if the destination LBAs have been scanned by BMS. If the LBAs have been verified, the drive proceeds with the normal write command. If the LBAs have not been verified by BMS, Pre-Scan will convert the write to a write verify to certify that the data was properly written to the disc.

Note. During Pre-Scan write verify commands, write performance may decrease by 50% until Pre-Scan completes. Write performance testing should be performed after Pre-Scan is complete. This may be checked by reading the BMS status.

To expedite the scan of the full pack and subsequently exit from the Pre-Scan period, BMS will begin scanning immediately when the drive goes to idle during the Pre-Scan period. In the event that the drive is in a high transaction traffic environment and is unable to complete a BMS scan within 24 power on hours BMS will dis- able Pre-Scan to restore full performance to the system.

7.6Deferred Auto-Reallocation

Deferred Auto-Reallocation (DAR) simplifies reallocation algorithms at the system level by allowing the drive to reallocate unreadable locations on a subsequent write command. Sites are marked for DAR during read oper- ations performed by the drive. When a write command is received for an LBA marked for DAR, the auto-reallo- cation process is invoked and attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

This is in contrast to the system having to use the Reassign Command to reassign a location that was unread- able and then generate a write command to rewrite the data. DAR is most effective when AWRE and ARRE are enabled—this is the default setting from the Seagate factory. With AWRE and ARRE disabled DAR is unable to reallocate the failing location and will report an error sense code indicating that a write command is being attempted to a previously failing location.

7.7Idle Read After Write

Idle Read After Write (IRAW) utilizes idle time to verify the integrity of recently written data. During idle periods, no active system requests, the drive reads recently written data from the media and compares it to valid write command data resident in the drives data buffer. Any sectors that fail the comparison result in the invocation of a rewrite and auto-reallocation process. The process attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

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Cheetah 15K.6 FC Product Manual, Rev. D

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Contents ST3300656FC ST3450856FCST3146356FC Page Contents Physical/electrical specifications Defect and error managementInstallation Interface requirementsSeagate Technology support services Cheetah 15K.6 FC Product Manual, Rev. D Scope Model Number Full Disk Encryption FDECheetah 15K.6 FC Product Manual, Rev. D Applicable standards and reference documentation StandardsElectromagnetic compatibility Electromagnetic susceptibilityEuropean Union Restriction of Hazardous Substances RoHS Reference documents Ncits TR-20Cheetah 15K.6 FC Product Manual, Rev. D General description Standard features Media description PerformanceReliability Formatted capacitiesFactory-installed options User-installed accessoriesPerformance characteristics Internal drive characteristicsSeek performance characteristics Access timeFormat command execution time minutes General performance characteristicsStart/stop time 176 144 100Cache operation Prefetch/multi-segmented cache controlCaching write data Prefetch operation Reliability 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 MillisecondsTemperature Log Page 0Dh Determining ratePredictive failures Thermal monitorState of the drive prior to testing Drive Self Test DSTDST failure definition ImplementationShort and extended tests Short test Function Code 001bExtended test Function Code 010b Log page entriesShipping Product warrantyProduct repair and return information Cheetah 15K.6 FC Product Manual, Rev. D AC power requirements Physical/electrical specificationsDC power requirements ST3450856FC DC power requirements Gbit Amps ST3450056FC DC power requirements Gbit AmpsST3300656FC DC power requirements Gbit Amps ST3300056FC DC power requirements Gbit AmpsST3146356FC DC power requirements Gbit Amps ST3146756FC DC power requirements Gbit AmpsGeneral DC power requirement notes Power sequencingConducted noise immunity Current profilesTypical ST3450856FC current profiles Typical ST3450056FC current profiles Typical ST3300656FC current profiles Typical ST3300056FC current profiles Typical ST3146356FC current profiles Typical ST3146756FC current profiles Power dissipation 450GB models300GB models Environmental limits Temperature146GB models Relative humidity Effective altitude sea levelShock and vibration Package size Packaged/product weight Drop heightShock Recommended mounting Air cleanliness VibrationAcoustics Corrosive environmentRoHS compliance statement Mechanical specifications Mounting configuration dimensionsDrive internal defects/errors Defect and error managementDrive error recovery procedures Page FC-AL system errors Background Media ScanDeferred Auto-Reallocation Media Pre-ScanIdle Read After Write Installation Drive ID/option selectionDrive orientation CoolingDrive mounting GroundingPage Cheetah 15K.6 FC Product Manual, Rev. D FC-AL features Fibre Channel link service framesLink services supported Type of frame Interface requirementsFibre Channel task management responses Fibre Channel task management functionsFC Scsi FCP response codes Function name Response code Fibre Channel port login NPort login Plogi payload BytesFibre Channel port login accept Fibre Channel Process LoginNPort Login Accept ACC payload Bytes Process Login Plri payloadFibre Channel Process Login Accept Fibre Channel fabric loginProcess Login Accept ACC payload Bytes Fabric Login Flogi payload BytesFibre Channel fabric accept login Fabric Login Accept ACC payload BytesScsi commands supported Dual port supportFibre Channel Arbitrated Loop options FC-AL options supportedSupported commands Cheetah 15K.6 FC Product Manual, Rev. D Cheetah 15K.6 FC Product Manual, Rev. D Supported commands Inquiry data Mode Sense dataCheetah 15K.6 FC inquiry data Bytes Data hex Page Mode Data Header 000000 Cheetah 15K.6 FC Product Manual, Rev. D Miscellaneous operating features and conditions Miscellaneous featuresSupported Feature or condition Miscellaneous statusFC-AL physical interface Physical characteristicsPhysical description Electrical description Connector requirementsPin descriptions Pin Signal name Signal type FC-SCA pin descriptions Pin Signal name Signal typeFC-AL transmitters and receivers Power Fault LED OutActive LED Out Enable port bypass signalsMotor start controls Parallel Enclosure Services Interface ESI 11 SEL6 through SEL0 ID linesArbitrated loop physical address Alpa values SettingHex Dec TTL input characteristics Signal characteristicsDevice control codes FC Differential output LED driver signalsFC Differential input Receive eye diagram Eye diagram data values Link rate GHz Cheetah 15K.6 FC Product Manual, Rev. D Seagate Technology support services InternetPresales Support Technical SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call CenterToll-freeDirect dialFAX Index NumericsFC-AL Flogi Plogi Page See also cooling
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ST3450856FC specifications

The Seagate ST3146356FC, ST3300656FC, and ST3450856FC are hard disk drives designed for enterprise storage solutions, showcasing Seagate’s commitment to performance, reliability, and advanced technology in the data storage sector. These drives cater primarily to the needs of data centers and businesses requiring robust data management capabilities.

The ST3146356FC is notable for its 146GB capacity, 3.5-inch form factor, and 10,000 RPM spindle speed. It employs Serial Attached SCSI (SAS) interface technology, which ensures high data transfer rates and reliable connectivity. This model is designed to handle a multitude of demanding applications, such as online transaction processing and enterprise resource planning, requiring fast access to data and minimized latency.

The ST3300656FC, with a capacity of 300GB, continues the trend of high performance set by its predecessor. This drive also features the 10,000 RPM spindle speed and SAS interface, providing enhanced data throughput and optimized performance for intensive workloads. The drive is built with advanced error recovery features that enhance data integrity and reliability, making it suitable for critical applications where data loss is unacceptable.

The ST3450856FC offers even greater capacity, with a robust 450GB storage option. Like the other models, it operates at 10,000 RPM and utilizes the SAS interface. This drive is designed for scalability, ensuring that it can meet the evolving storage demands of enterprises. It is also equipped with sophisticated technologies such as Seagate's Enhanced S.M.A.R.T. (Self-Monitoring, Analysis, and Reporting Technology), providing continual monitoring of the drive’s health and performance metrics.

All three models share key characteristics, including advanced thermal and power management technologies that help maintain optimal operating temperatures and reduce energy consumption. This is crucial in data center environments where maximizing efficiency is vital for operational cost management. Additionally, Seagate's commitment to low acoustic noise levels ensures quieter operation, which is beneficial in environments where sound levels must be controlled.

In summary, the Seagate ST3146356FC, ST3300656FC, and ST3450856FC drives are engineered for enterprise environments demanding high reliability, speed, and capacity. Their advanced technologies, including SAS interface and enhanced error management systems, make these drives ideal for critical applications in data-intensive sectors. With reinforced durability, effectiveness in managing large volumes of data, and a focus on energy efficiency, these drives symbolize the pinnacle of Seagate's storage innovations for enterprise solutions.