Seagate ST31000640FC, ES.2 FC manual Cache operation, Caching write data

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All default cache and prefetch mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given in Section 9.3.2

4.5Cache operation

Note. Refer to the Fibre Channel Interface Manual for more detail concerning the cache bits.

Of the 16 Mbytes physical buffer space in the drive, approximately 13,000 kbytes can be used as a cache. The buffer is divided into logical segments from which data is read and to which data is written.

The drive keeps track of the logical block addresses of the data stored in each segment of the buffer. If the cache is enabled (see RCD bit in the FC Interface Manual), data requested by the host with a read command is retrieved from the buffer, if possible, before any disc access is initiated. If cache operation is not enabled, the buffer is still used, but only as circular buffer segments during disc medium read operations (disregarding Prefetch operation for the moment). That is, the drive does not check in the buffer segments for the requested read data, but goes directly to the medium to retrieve it. The retrieved data merely passes through some buffer segment on the way to the host. All data transfers to the host are in accordance with buffer-full ratio rules. See the explanation provided with the information about Mode Page 02h (disconnect/reconnect control) in the Fibre Channel Interface Manual.

The following is a simplified description of the prefetch/cache operation:

Case A—read command is received and all of the requested logical blocks are already in the cache:

1. Drive transfers the requested logical blocks to the initiator.

Case B—A Read command requests data, and at least one requested logical block is not in any segment of the cache:

1.The drive fetches the requested logical blocks from the disc and transfers them into a segment, and then from there to the host in accordance with the Mode Select Disconnect/Reconnect parameters, page 02h.

2.If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.

Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blocks. The drive dynamically creates and removes segments based on the workload. The wrap-around capa- bility of the individual segments greatly enhances the cache’s overall performance.

Note. The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15. The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size specification using the Mode Select command (bytes 14 and 15) does not set up a new segment size. If the STRICT bit in Mode page 00h (byte 2, bit 1) is set to one, the drive responds as it does for any attempt to change an unchangeable parameter.

4.5.1Caching write data

Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to be written to the medium is stored while the drive performs the Write command.

If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made avail- able for future read cache hits. The same buffer space and segmentation is used as set up for read functions. The buffer segmentation scheme is set up or changed independently, having nothing to do with the state of RCD. When a write command is issued, if RCD=0, the cache is first checked to see if any logical blocks that are to be written are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The new data is cached for subsequent Read commands.

If the number of write data logical blocks exceed the size of the segment being written into, when the end of the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data that was written there at the beginning of the operation; however, the drive does not overwrite data that has not yet been written to the medium.

Barracuda ES.2 FC Product Manual, Rev. B

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Contents ST31000640FC Barracuda ES.2 FCPage Barracuda ES.2 FC Product Manual, Rev. B Barracuda ES.2 FC Product Manual, Rev. B Contents Defect and error management Physical/electrical specificationsInstallation Interface requirementsSeagate Technology support services Barracuda ES.2 FC Product Manual, Rev. B Scope Barracuda ES.2 FC Product Manual, Rev. B Standards Standards, compliance and reference documentsElectromagnetic compatibility Electromagnetic susceptibilityCompliance Ncits TR-19 Reference documentsBarracuda ES.2 FC Product Manual, Rev. B General description Media description Standard featuresReliability PerformanceFormatted capacities Programmable drive capacityUser-installed accessories Factory-installed optionsInternal drive characteristics Performance characteristicsAccess time Format command execution time minutesGeneral performance characteristics Start/stop timePrefetch/multi-segmented cache control Caching write data Cache operationPrefetch operation Error rates Reliability specificationsRecoverable Errors Unrecoverable ErrorsSeek errors Reliability and serviceInterface errors Preventive maintenanceControlling S.M.A.R.T 4 S.M.A.R.TPerformance impact MillisecondsDetermining rate Reporting controlPredictive failures Thermal monitorParameter Code Description State of the drive prior to testingDrive Self Test DST DST failure definitionShort and extended tests Invoking DSTShort test Function Code 001b Extended test Function Code 010bAbort Product warrantyShipping Product repair and return informationBarracuda ES.2 FC Product Manual, Rev. B AC power requirements Physical/electrical specificationsDC power requirements DC power requirements Gbit AmpsGeneral DC power requirement notes Power sequencingConducted noise immunity Current profiles Power dissipation Temperature Environmental limitsRelative humidity Effective altitude sea level Package size Packaged/product weight Drop heightShock and vibration ShockVibration Air cleanlinessAcoustics Corrosive environmentChina Restriction of Hazardous Substances RoHS Directive X表示该部件（于同类物品程度上）所含的危险和有毒物质中国RoHS MCV标准所定义的门槛值。Mounting configuration dimensions Mechanical specificationsBarracuda ES.2 FC Product Manual, Rev. B Defect and error management Drive internal defects/errorsDrive error recovery procedures 51.87 FC-AL system errors Background Media ScanMedia Pre-Scan Idle Read After Write Deferred Auto-ReallocationDrive ID/option selection InstallationDrive orientation CoolingAir flow Drive mountingGrounding Barracuda ES.2 FC Product Manual, Rev. B Fibre Channel link service frames FC-AL featuresLink services supported Type of frame Interface requirementsFibre Channel task management functions Fibre Channel task management responsesFC Scsi FCP response codes Function name Response code NPort login Plogi payload Bytes Fibre Channel port loginFibre Channel Process Login Fibre Channel port login acceptNPort Login Accept ACC payload Bytes Process Login Plri payloadFibre Channel fabric login Fibre Channel Process Login AcceptProcess Login Accept ACC payload Bytes Fabric Login Flogi payload BytesFabric Login Accept ACC payload Bytes Fibre Channel fabric accept loginFibre Channel Arbitrated Loop options Dual port supportFC-AL options supported Option SupportedSupported commands Command code Command name Scsi commands supportedVerify error recovery page 07h Barracuda ES.2 FC Product Manual, Rev. B Temperature page 0Dh Mode Sense data Inquiry dataBarracuda ES.2 FC inquiry data Bytes Data hex Page Block Descriptor Mode Sense Pages Data Miscellaneous features Miscellaneous operating features and conditionsSupported Feature or condition Miscellaneous statusPhysical characteristics FC-AL physical interfacePhysical description Connector requirements Electrical descriptionPin descriptions FC-SCA pin descriptions Pin Signal name Signal type Pin Signal name Signal typeFC-AL transmitters and receivers Fault LED Out PowerEnable port bypass signals Active LED OutMotor start controls 11 SEL6 through SEL0 ID lines Parallel Enclosure Services Interface ESISetting Arbitrated loop physical address Alpa valuesHex Dec Signal characteristics TTL input characteristicsDevice control codes LED driver signals FC Differential outputFC Differential input Receive eye diagram Eye diagram data values Link rate GHz Barracuda ES.2 FC Product Manual, Rev. B Internet Seagate Technology support servicesPresales Support Technical SupportWarranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call Center Toll-free Direct dial Numerics IndexFAN Flogi Plogi SEL ID See also cooling

ST31000640FC, ES.2 FC specifications

The Seagate ES.2 FC, model ST31000640FC, is a high-performance hard drive designed specifically for enterprise environments. This drive is engineered to provide reliable and efficient data storage, catering to the demands of critical business applications, data centers, and server infrastructures.

One of the standout features of the ST31000640FC is its large storage capacity. With a 1TB capacity, it offers ample space for storing vast amounts of data, making it an excellent choice for businesses that require extensive storage solutions. This capacity enables the drive to support extensive databases, applications, and virtualized environments without compromising performance.

The Seagate ES.2 FC utilizes Fibre Channel (FC) interface technology, which is known for its high-speed data transfer capabilities. Operating at 4 Gbps, this interface facilitates faster communication between the drive and the server, significantly enhancing overall system performance. The Fibre Channel technology also improves data integrity through its ability to manage large amounts of data traffic efficiently.

In terms of performance specifications, the ST31000640FC boasts a rotational speed of 7200 RPM and a sustained data transfer rate that offers quick access to information. Additionally, it features an advanced caching mechanism that optimizes read and write operations, ensuring rapid data retrieval and improved application responsiveness.

The drive's advanced error recovery and data protection mechanisms, such as the Seagate PowerTrim technology, work to minimize downtime and data loss. This is particularly crucial for enterprise applications that demand high availability and reliability. PowerTrim intelligently manages the drive’s internal resources to enhance performance and durability.

Another essential characteristic of the Seagate ES.2 FC is its enterprise-grade reliability. It boasts a mean time between failures (MTBF) rating of 1.2 million hours, indicating its robustness for continuous operation in demanding environments. Furthermore, it is designed to operate in a range of temperatures, ensuring consistent performance across various operational conditions.

Lastly, the Seagate ES.2 FC incorporates vibration tolerance and advanced acoustic performance features, which help to reduce noise and ensure quieter operation in data center environments. This makes it an attractive option for enterprises looking to optimize their infrastructure while minimizing disturbances.

In summary, the Seagate ES.2 FC, ST31000640FC hard drive is an excellent choice for enterprises seeking a balance of large storage capacity, high-speed performance, and reliability in a Fibre Channel environment. With its array of technologies and robust characteristics, it meets the rigorous demands of modern business storage needs.
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