Re: RES: Disk saturation
Regarding these weird messages in the dmesg output:
sda: asking for cache data failed
sda: assuming drive cache: write through
Does it mean that scsi controller does not have cache?
And even if there is cache in the controller does message mean that it
will
not be used?
Sorry for the late reply.
I've seen exactly this message on some of my hardware RAIDS. For me, it
does mean that the cache on the RAID controller will not be used. I
believe it means the same for you.
That could be part of your latency issue. write-through is supposed to be
slower than cached as it has to wait for the operation to finish. This
could be faulty logic due to incomplete information though...
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