Opened 11 years ago

Closed 11 years ago

#250 closed enhancement (fixed)

implement -g/-s wcache and lookahead for the SCSI drvies

Reported by: Alex Samorukov Owned by: somebody
Priority: minor Milestone: Release 6.1
Component: all Version: 6.0
Keywords: scsi Cc:

Description (last modified by Alex Samorukov)

Most of SCSI/SAS drives are supporting cache control, so it is possible to implement this functionality. This should help a lot for SAS drives behind the RAID - some of them turning off write cache if drive is not "native".

Tested on scsi, megaraid and cciss device types on Linux. It was found that cciss silently filtering MODE SELECT command, so actual values are not changed. On megaraid and direct connection everything works as expected.

Change History (2)

comment:1 by Alex Samorukov, 11 years ago

corresponding settings are "Writeback Cache Enable" (WCE) and clear "Read Cache Disable" (RCD) bits in mode page CACHING_PAGE (0x08)

comment:2 by Alex Samorukov, 11 years ago

Description: modified (diff)
Milestone: Release 6.1
Resolution: fixed
Status: newclosed

Implemented in r3703-3708. Instead of using "lookahead" new "rcache" setting was added, because "readahead" has very different meaning.

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