From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: Implementing low level timeouts within MD Date: Tue, 30 Oct 2007 13:39:44 -0400 Message-ID: <1193765984.10336.519.camel@firewall.xsintricity.com> References: <1193418753.4771.17.camel@w100> <1193425254.10336.290.camel@firewall.xsintricity.com> <87tzoc7soa.fsf@willow.rfc1149.net> <1193721577.3876.12.camel@w100> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-v4NJhXEi3+jvy19ysLw6" Return-path: In-Reply-To: <1193721577.3876.12.camel@w100> Sender: linux-raid-owner@vger.kernel.org To: Alberto Alonso Cc: Samuel Tardieu , linux-raid@vger.kernel.org List-Id: linux-raid.ids --=-v4NJhXEi3+jvy19ysLw6 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable 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. > >=20 > > Sam >=20 > 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. --=20 Doug Ledford GPG KeyID: CFBFF194 http://people.redhat.com/dledford Infiniband specific RPMs available at http://people.redhat.com/dledford/Infiniband --=-v4NJhXEi3+jvy19ysLw6 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQBHJ2xfTzP9PM7pjw8RAnlkAJ9HPUAQdl6pc6QdG5N/kYcGQsncIgCcDy2C hDktsPzp/q+49cfs+GsVfSY= =zwL6 -----END PGP SIGNATURE----- --=-v4NJhXEi3+jvy19ysLw6--