Kernel assuming write caching on iSCSI device

[spatuality]

Hi list,

I'm having trouble connecting to a Promise M500i iSCSI disk array. 2/4 servers connect fine with iscsi-initiator-utils-4.0.3.0-4. The other 2 servers have this in dmesg:

SCSI device sdb: 1 512-byte hdwr sectors (0 MB)
sdb: asking for cache data failed
sdb: assuming drive cache: write through
SCSI device sdb: 1 512-byte hdwr sectors (0 MB)
sdb: asking for cache data failed
sdb: assuming drive cache: write through
sdb:<6>Device sdb not ready.
end_request: I/O error, dev sdb, sector 0
Buffer I/O error on device sdb, logical block 0
Device sdb not ready.
end_request: I/O error, dev sdb, sector 0
Buffer I/O error on device sdb, logical block 0
Device sdb not ready.
end_request: I/O error, dev sdb, sector 0
Buffer I/O error on device sdb, logical block 0
Attached scsi disk sdb at scsi1, channel 0, id 0, lun 0


The drive does not allow connections after this failed attempt at guessing the write cache type.

Is there a way to hard-code the write cache setting on the server? Anyone experience this with other hardware/iscsi/promise devices?


Brian

[spatuality]

NM. I checked kernel-2.6.9 source. It seems that this messages was produced via drivers/scsi/sd.c on lines 1303 & line:1308 in sd.c file. Its a known kernel bug.