From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1RBz20-00075S-QA for garchives@archives.gentoo.org; Fri, 07 Oct 2011 01:15:21 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id A1C8B21C11A; Fri, 7 Oct 2011 01:15:11 +0000 (UTC) Received: from mail-bw0-f53.google.com (mail-bw0-f53.google.com [209.85.214.53]) by pigeon.gentoo.org (Postfix) with ESMTP id BA5B121C075 for ; Fri, 7 Oct 2011 01:14:18 +0000 (UTC) Received: by bkbzt12 with SMTP id zt12so5261976bkb.40 for ; Thu, 06 Oct 2011 18:14:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=O5Zeo+SXX33xH8sw1ZwR+JDky1rTbFc4N30bfRXytq0=; b=PprW1ZdUJwJicmjTgxbvvP+6ZEenK5YBT02BoLAl/dzo8YEqAm085SZg5xSc1u4j6S apYfPUt6QfQADSXl2M+kmtub3bZ4uNfZstZ9N9pmv7O3YupwsOBqoF5OOBFI5ViwwheT LgW9MZgI3s/yWxX2a/lDUWsGMOMlAv3F+y1SA= Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.204.144.202 with SMTP id a10mr893865bkv.337.1317950057857; Thu, 06 Oct 2011 18:14:17 -0700 (PDT) Received: by 10.204.177.199 with HTTP; Thu, 6 Oct 2011 18:14:17 -0700 (PDT) Received: by 10.204.177.199 with HTTP; Thu, 6 Oct 2011 18:14:17 -0700 (PDT) In-Reply-To: References: <4E8DFE1B.6060403@gmail.com> Date: Thu, 6 Oct 2011 21:14:17 -0400 Message-ID: Subject: Re: [gentoo-user] How can I power disk off? From: Michael Mol To: gentoo-user@lists.gentoo.org Content-Type: multipart/alternative; boundary=0015174a0e4807c49704aeab29bb X-Archives-Salt: X-Archives-Hash: d4240b3ec9198804c6fe904d8a20dd01 --0015174a0e4807c49704aeab29bb Content-Type: text/plain; charset=UTF-8 On Oct 6, 2011 9:06 PM, "Mark Knecht" wrote: > > On Thu, Oct 6, 2011 at 1:28 PM, Michael Mol wrote: > > On Thu, Oct 6, 2011 at 4:21 PM, Mark Knecht wrote: > >> On Thu, Oct 6, 2011 at 1:03 PM, Paul Hartman > >> My worry was that if the mdraid daemon saw one drive gone - either > >> when starting to spin down or when one spins up slowly - and if mdraid > >> didn't understand that all this stuff was taking place intentionally > >> then it might mark that drive as having failed. > > > > Does mdraid even have an awareness of timeouts, or does it leave that > > to lower drivers? I think the latter condition is more likely. > > > > I suspect, though, that if your disk fails to spin up reasonably > > quickly, it's already failed. > > > > In general I agree. However drives that are designed for RAID have a > feature known as Time Limited Error Recovery (TLER) which supposedly > guarantees that they'll get the drive back to responding fast enough > to not have it marked as failed in the RAID array: > > http://en.wikipedia.org/wiki/Time-Limited_Error_Recovery > > When I built my first RAID I bought some WD 1TB green drives, built > the RAID and immediately had drives failing because they didn't have > this sort of feature. I replaced them with RAID Edition drives that > have the TLER feature and have never had a problem since. (Well, I > actually bought all new drives and kept the six 1TB drives which I'd > mostly used up for other things like external eSATA backup drives, > etc...) > > Anyway, I'm possibly over sensitized to this sort of timing problem > specifically in a RAID which is why I asked the question of Paul in > the first place. My first RAID was with three Seagate economy 1.5TB drives in RAID 5, shortly followed by three 1TB WD black drives in RAID 0. I never had the problems you describe, though I rebuit the RAID5 several times as I was figuring things out. (the 3TB RAID0 was for some heavy duty scratch space.) --0015174a0e4807c49704aeab29bb Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Oct 6, 2011 9:06 PM, "Mark Knecht" <markknecht@gmail.com> wrote:
>
> On Thu, Oct 6, 2011 at 1:28 PM, Michael Mol <mikemol@gmail.com> wrote:
> > On Thu, Oct 6, 2011 at 4:21 PM, Mark Knecht <markknecht@gmail.com> wrote:
> >> On Thu, Oct 6, 2011 at 1:03 PM, Paul Hartman
> >> My worry was that if the mdraid daemon saw one drive gone - e= ither
> >> when starting to spin down or when one spins up slowly - and = if mdraid
> >> didn't understand that all this stuff was taking place in= tentionally
> >> then it might mark that drive as having failed.
> >
> > Does mdraid even have an awareness of timeouts, or does it leave = that
> > to lower drivers? I think the latter condition is more likely. > >
> > I suspect, though, that if your disk fails to spin up reasonably<= br> > > quickly, it's already failed.
> >
>
> In general I agree. However drives that are designed for RAID have a > feature known as Time Limited Error Recovery (TLER) which supposedly > guarantees that they'll get the drive back to responding fast enou= gh
> to not have it marked as failed in the RAID array:
>
> h= ttp://en.wikipedia.org/wiki/Time-Limited_Error_Recovery
>
> When I built my first RAID I bought some WD 1TB green drives, built > the RAID and immediately had drives failing because they didn't ha= ve
> this sort of feature. I replaced them with RAID Edition drives that > have the TLER feature and have never had a problem since. (Well, I
> actually bought all new drives and kept the six 1TB drives which I'= ;d
> mostly used up for other things like external eSATA backup drives,
> etc...)
>
> Anyway, I'm possibly over sensitized to this sort of timing proble= m
> specifically in a RAID which is why I asked the question of Paul in > the first place.

My first RAID was with three Seagate economy 1.5TB drives in RAID 5, sho= rtly followed by three 1TB WD black drives in RAID 0. I never had the probl= ems you describe, though I rebuit the RAID5 several times as I was figuring= things out. (the 3TB RAID0 was for some heavy duty scratch space.)

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