Sas System Errors - Seagate Savvio 10K Product Manual

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
1
Read retry count LBA (cumulative, msec)
0 51.97
1 59.97
2 203.9
3 219.9
4 243.9
5 275.9
6 347.8
7 355.8
8 371.8
9 407.8
10 444.4
11 (default) 980.1
[1] Setting these retry counts to a value below the default setting could result in degradation of the unrecov-
ered 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 4-block read command can take up to 244 msec
recovery time for each block and a maximum of 450 msec recovery for all four blocks. If either of these
limits is reached and a block has not yet been recovered, the command will end with Check Condition sta-
tus and an unrecoverable read error will be reported.
7.3

SAS 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.
40
Maximum recovery time per
1
Write retry count
LBA (cumulative, msec)
0 24.0
1 36.0
2 40.0
3 76.0
4 151.9
5 (default) 179.9
Savvio SAS Product Manual, Rev. D