Re: SCSI "asking for cache data failed"

From: Jens Axboe
Date: Thu Oct 13 2005 - 07:30:30 EST


On Thu, Oct 13 2005, Alan Cox wrote:
> On Iau, 2005-10-13 at 12:45 +0200, Marcin Owsiany wrote:
> > I'm wondering about the following messages, which appeared when I upgraded from
> > 2.4 to 2.6:
> >
> > | sda: asking for cache data failed
> > | sda: assuming drive cache: write through
> >
> > (a larger log snippet below)
>
> The kernel asks the SCSI drive for its cache parameters. The AMI raid
> card sitting in the middle doesn't know how to handle this so this
> message occurs. It should be ok providing the raid card itself is
> handling the consistency correctly but check with your card vendor.

The assumption that sd makes might be a little on the risky side though,
would seem a lot safer to assume write back if you don't know the
policy. At least that wont bring surprises later on...

--
Jens Axboe

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