CAM//SCSI disk timeouts
julian at vicor.com
Tue Jan 20 13:18:01 PST 2004
If we are talkign to a raid array and it discovers that it has to
do some maintanance (e.g. declare a physical disk bad or recreate
some data on the fly) it is possible that transactions to the raid
that are outstanding may tak a lot longer than usual. In particular,
we've seen the case where a log entry in teh Raid controller's log
that indicates that a drive has been declared bad, is often accompanied
in FreeBSD with a set of CAM /scsi-disk timeouts
and things degrade from there...
Where can I find the timeouts in force fo rscsi disks and teh retry policies?
I need to compare the theoretical behaviour of FreeBSD CAM with the
theoretical timeouts needed for the raid array, given a disk failure..
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