Table 6 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 recov- ery 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 6: 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

35.94

 

 

1

53.91

 

 

2

79.89

 

 

3

97.86

 

 

4

175.85

 

 

5 (default)

421.79

 

 

*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 com- mands 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.

Savvio 10K.5 SAS Product Manual, Rev. D

49

Page 56 Page 58
Page 57
Image 57
Seagate ST9300605SS, ST9900605SS, ST9900805SS, ST9900705SS, ST9600005SS, ST9600105SS SAS system errors, Background Media Scan
Page 56 Page 58

ST9600005SS, ST9600205SS, ST9300505SS, ST9300605SS, ST9300405SS specifications

Seagate has long been a prominent player in the storage solutions market, offering a range of hard drives that cater to various needs and applications. Among its extensive lineup, the Seagate ST9600105SS, ST9450405SS, ST9450305SS, ST9900605SS, and ST9900805SS stand out due to their unique features and robust performance, making them suitable for both personal and professional use.

The Seagate ST9600105SS is a 2.5-inch 600GB SAS hard drive that delivers exceptional reliability and performance. With a rotational speed of 10,000 RPM, this drive ensures quick data access through its enhanced data transfer rate. It utilizes a SAS 6Gb/s interface, allowing for fast and efficient data management in enterprise environments. The drive is designed with Seagate's AgileArray technology, which optimizes drive reliability for multi-drive environments, ensuring that users benefit from reduced downtime.

Similarly, the ST9450405SS and ST9450305SS are also 2.5-inch SAS drives, offering capacities of 450GB and 300GB, respectively. Both models feature a 10,000 RPM speed and a 6Gb/s SAS interface, making them ideal for use in data centers and business-critical applications. The ST9450405SS has enhanced power efficiency, aiding in lowering operational costs for enterprises. Both drives incorporate Seagate's advanced error recovery controls, which help maintain data integrity under varying workloads.

On the larger capacity side, the Seagate ST9900605SS and ST9900805SS drives provide even more storage options. Offering 600GB and 800GB capacities, respectively, these drives are designed for high-performance computing environments. They also spin at 10,000 RPM and support the 6Gb/s SAS interface. The ST9900805SS, in particular, is noted for its advanced performance in transactional workloads, making it suitable for database storage, virtualization, and analytics.

All five models feature Seagate’s innovative technologies, including firmware enhancements for improved error correction and reliability. They are also built to operate in a variety of environments, offering robust vibration tolerance.

In summary, the Seagate ST9600105SS, ST9450405SS, ST9450305SS, ST9900605SS, and ST9900805SS represent some of the best storage solutions for high-demand applications. With their emphasis on performance, reliability, and energy efficiency, these drives are engineered to meet the challenges of modern data storage needs, ensuring organizations can rely on them for their critical operations.
Top Page Image Contents