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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 14: Read and write retry count maximum recovery times
| Maximum recovery time per |
Read retry count | LBA (cumulative, msec) |
|
|
|
|
0 | 67.43 |
|
|
1 | 77.81 |
|
|
2 | 264.54 |
|
|
3 | 300.85 |
|
|
4 | 344.60 |
|
|
5 | 378.72 |
|
|
6 | 420.21 |
|
|
7 | 529.22 |
|
|
8 | 617.62 |
|
|
9 | 659.11 |
|
|
10 | 705.80 |
|
|
11 (default) | 1693.67 |
|
|
Write retry count | Maximum recovery time per |
LBA (cumulative, msec) | |
|
|
|
|
0 | 31.12 |
|
|
1 | 46.68 |
|
|
2 | 72.62 |
|
|
3 | 88.18 |
|
|
4 | 155.73 |
|
|
5 (default) | 192.04 |
|
|
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, the read retry count set to 4, and the recovery time limit set to 450. A
7.3SAS 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.
7.4Background Media Scan
Background Media Scan (BMS) is a
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
Savvio 10K.2 SAS Product Manual, Rev. D | 39 |