On Tue, 2007-10-30 at 00:19 -0500, Alberto Alonso wrote:
> On Sat, 2007-10-27 at 12:33 +0200, Samuel Tardieu wrote:
> > I agree with Doug: nothing prevents you from using md above very slow
> > drivers (such as remote disks or even a filesystem implemented over a
> > tape device to make it extreme). Only the low-level drivers know when
> > it is appropriate to timeout or fail.
> >
> > Sam
>
> The problem is when some of these drivers are just not smart
> enough to keep themselves out of trouble. Unfortunately I've
> been bitten by apparently too many of them.
Really, you've only been bitten by three so far. Serverworks PATA
(which I tend to agree with the other person, I would probably chock
this up to Serverworks, not PATA), USB storage, and SATA (the SATA stack
is arranged similar to the SCSI stack with a core library that all the
drivers use, and then hardware dependent driver modules...I suspect that
since you got bit on three different hardware versions that you were in
fact hitting a core library bug, but that's just a suspicion and I could
well be wrong). What you haven't tried is any of the SCSI/SAS/FC stuff,
and generally that's what I've always used and had good things to say
about. I've only used SATA for my home systems or workstations, not any
production servers.
> I'll repeat my plea one more time. Is there a published list
> of tested combinations that respond well to hardware failures
> and fully signals the md code so that nothing hangs?
I don't know of one, but like I said, I've not used a lot of the SATA
stuff for production. I would make this one suggestion though, SATA is
still an evolving driver stack to a certain extent, and as such, keeping
with more current kernels than you have been using is likely to be a big
factor in whether or not these sorts of things happen.
> If not, I would like to see what people that have experienced
> hardware failures and survived them are using so that such
> a list can be compiled.
--
Doug Ledford <dledford@xxxxxxxxxx>
GPG KeyID: CFBFF194
http://people.redhat.com/dledford
Infiniband specific RPMs available at
http://people.redhat.com/dledford/Infiniband
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