HP LTO 4 SAS, LTO 4 FC, LTO 4 SCSI manual RWW retry counts, Corrective action

RWW retry counts

Data is read immediately after being written to tape to establish that it has been written correctly. Increases in RWW retries can be due to four factors:

•Deterioration in the media

•Dirty heads

•Drive malfunction

•The operating environment

Corrective action

The recommended criteria for corrective action are as follows:

RWW Retries > 5% Total data sets written

When using tapes without write-protection, use the Total count.

The corrective action should be as follows:

1.Use another tape and, for a write operation, try repeating the write. For a read operation, try reading data from the tape.

2.See whether the current RWW value is within the recommended limit.

3.If the values are now within the limit, you can assume that the original tape is nearing the end of its useful life. Proceed as follows:

•For a write operation, discard the tape and use a new one.

•For a read operation, transfer the data to a new tape.

4.If the value is still outside the limit, clean the tape heads with a cleaning cartridge and try repeating the operation with the original tape.

26 Use of tapes

HP restricted