Table 3 equates the read and write retry count with the maximum possible recovery time for read and write recovery of individual LBAs. The times given do not include time taken to perform reallocations. Reallocations are performed when the ARRE bit (for reads) or AWRE bit (for writes) is one, the RC bit is zero, and the recovery time limit for the command has not yet been met. Time needed to perform reallocation is not counted against the recovery time limit.

When the RC bit is one, reallocations are disabled even if the ARRE or AWRE bits are one. The drive will still perform data recovery actions within the limits defined by the Read Retry Count, Write Retry Count, and Recovery Time Limit parameters. However, the drive does not report any unrecovered errors.

Table 3: Read and write retry count maximum recovery times

 

Maximum recovery time per

Read retry count*

LBA (cumulative, msec)

 

 

 

 

1

124.32

 

 

5

621.62

 

 

10

1243.23

 

 

15

1864.85

 

 

20 (default)

2486.47

 

 

Write retry count

Maximum recovery time per

LBA (cumulative, msec)

 

 

0

23.94

 

 

1

35.91

 

 

2

55.86

 

 

3

67.83

 

 

4

119.79

 

 

5 (default)

147.72

 

 

*For read retry count, every tick ~ 5% of total error recovery. Valid range setting is 1-20. e.g. 1 ~ 5%

5 ~ 25%

20 ~ 100%

Setting these retry counts to a value below the default setting could result in degradation of the unrecovered error rate. For example, suppose the read/write recovery page has the RC bit = 0 and if the read retry count is set to 5, this means ~ 25% of error recovery will be executed which consumes 621.62 ms (please refer to the table above). If the limit is reached and a LBA has not yet been recovered (i.e. requires retries beyond 621.62 ms), the command will end with Check Condition status report and unrecoverable read error will be reported.

10.3SAS system errors

Information on the reporting of operational errors or faults across the interface is given in the SAS Interface Manual. The SSP Response returns information to the host about numerous kinds of errors or faults. The Receive Diagnostic Results reports the results of diagnostic operations performed by the drive.

Status returned by the drive to the initiator is described in the SAS Interface Manual. Status reporting plays a role in systems error management and its use in that respect is described in sections where the various commands are discussed.

10.4Background Media Scan

Background Media Scan (BMS) is a self-initiated media scan. BMS is defined in the T10 document SPC-4 available from the T10 committee. BMS performs sequential reads across the entire pack of the media while the drive is idle. In RAID arrays, BMS 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 BMS Log Page, it can avoid placing data in suspect locations on the media. Unreadable and recovered error sites will be logged or reallocated per ARRE/AWRE settings.

Constellation ES.2 SAS Product Manual, Rev. D

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Seagate ST33000651SS, ST33000652SS, ST33000650SS manual SAS system errors, Background Media Scan
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ST33000652SS, ST33000650SS, ST33000651SS specifications

The Seagate ST33000651SS, ST33000650SS, and ST33000652SS are high-performance enterprise hard drives designed for demanding storage applications. These models are part of the Seagate Constellation ES series, known for their reliability and performance in server and data center environments.

One of the most notable features of these drives is their capacity. The ST33000651SS and ST33000650SS offer a storage capacity of 3TB, providing ample space for data-intensive applications. The ST33000652SS enhances this with a larger storage option, ensuring that organizations can meet growing data demands without needing frequent upgrades.

These drives utilize a SATA 6Gb/s interface, which allows for high-speed data transfer. This increased bandwidth is essential for applications that rely on rapid access, such as virtualization, cloud computing, and database management systems. Additionally, the drives support Native Command Queuing (NCQ), which enhances performance by optimizing the order in which read and write commands are executed.

Reliability is paramount in enterprise environments, and Seagate addresses this with several technologies designed to minimize downtime. The ST33000651SS and its counterparts feature a 7200 RPM spindle speed, which not only delivers fast access times but also contributes to the overall durability of the drives. They also come with advanced error correction and data integrity features, which safeguard against data loss.

Another important characteristic of these drives is their low power consumption. Operating at an average power usage of 6.0W, they help reduce operational costs, particularly in large-scale deployments. This energy efficiency is essential for organizations looking to maintain sustainability while maximizing performance.

In terms of physical design, these hard drives are built to endure tough conditions typically found in data centers. They come in a standard 3.5-inch form factor, ensuring compatibility with a wide range of servers and storage enclosures. The robust design further enhances their lifespan, making them a sound investment for enterprise storage solutions.

In summary, the Seagate ST33000651SS, ST33000650SS, and ST33000652SS hard drives offer a compelling combination of high capacity, fast data transfer rates, and reliability. Their advanced technologies and energy-efficient design make them ideal choices for enterprises that require dependable and high-performing storage solutions in their IT infrastructure.
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