From: David Chinner <dgc@sgi.com>
To: David Chinner <dgc@sgi.com>,
Valerie Henson <val@vahconsulting.com>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org, "Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger@clusterfs.com>, Ric Wheeler <ric@emc.com>
Subject: Re: [RFC] Parallelize IO for e2fsck
Date: Tue, 22 Jan 2008 19:16:39 +1100 [thread overview]
Message-ID: <20080122081639.GV155259@sgi.com> (raw)
In-Reply-To: <20080122070511.GN3180@webber.adilger.int>
On Tue, Jan 22, 2008 at 12:05:11AM -0700, Andreas Dilger wrote:
> On Jan 22, 2008 14:38 +1100, David Chinner wrote:
> > On Mon, Jan 21, 2008 at 04:00:41PM -0700, Andreas Dilger wrote:
> > > I discussed this with Ted at one point also. This is a generic problem,
> > > not just for readahead, because "fsck" can run multiple e2fsck in parallel
> > > and in case of many large filesystems on a single node this can cause
> > > memory usage problems also.
> > >
> > > What I was proposing is that "fsck.{fstype}" be modified to return an
> > > estimated minimum amount of memory needed, and some "desired" amount of
> > > memory (i.e. readahead) to fsck the filesystem, using some parameter like
> > > "fsck.{fstype} --report-memory-needed /dev/XXX". If this does not
> > > return the output in the expected format, or returns an error then fsck
> > > will assume some amount of memory based on the device size and continue
> > > as it does today.
> >
> > And while fsck is running, some other program runs that uses
> > memory and blows your carefully calculated paramters to smithereens?
>
> Well, fsck has a rather restricted working environment, because it is
> run before most other processes start (i.e. single-user mode). For fsck
> initiated by an admin in other runlevels the admin would need to specify
> the upper limit of memory usage. My proposal was only for the single-user
> fsck at boot time.
The simple case. ;)
Because XFS has shutdown features, it's not uncommon to hear about
people running xfs_repair on an otherwise live system. e.g. XFS
detects a corrupted block, shuts down the filesystem, the admin
unmounts it, runs xfs_repair, puts it back online. meanwhile, all
the other filesystems and users continue unaffected. In this use
case, getting feedback about memory usage is, IMO, very worthwhile.
Cheers,
Dave.
--
Dave Chinner
Principal Engineer
SGI Australian Software Group
next prev parent reply other threads:[~2008-01-22 8:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <70b6f0bf0801161322k2740a8dch6a0d6e6e112cd2d0@mail.gmail.com>
2008-01-16 21:30 ` [RFC] Parallelize IO for e2fsck Valerie Henson
2008-01-18 1:15 ` David Chinner
2008-01-18 1:43 ` Valerie Henson
2008-01-21 23:00 ` Andreas Dilger
2008-01-22 3:38 ` David Chinner
2008-01-22 4:17 ` Valdis.Kletnieks
2008-01-22 7:00 ` Andreas Dilger
2008-01-22 13:05 ` Alan Cox
2008-01-22 14:40 ` Theodore Tso
2008-01-22 14:57 ` Arnaldo Carvalho de Melo
2008-01-28 19:30 ` Pavel Machek
2008-01-28 19:56 ` Theodore Tso
2008-01-28 20:01 ` Pavel Machek
2008-02-03 13:51 ` KOSAKI Motohiro
2008-01-29 8:29 ` david
2008-01-22 7:05 ` Andreas Dilger
2008-01-22 8:16 ` David Chinner [this message]
2008-01-22 17:42 ` Bryan Henderson
[not found] <9Mo9w-7Ws-25@gated-at.bofh.it>
[not found] ` <9Mo9w-7Ws-23@gated-at.bofh.it>
[not found] ` <9OdWm-7uN-25@gated-at.bofh.it>
[not found] ` <9Oi9A-5EJ-3@gated-at.bofh.it>
[not found] ` <9OiMg-6IC-1@gated-at.bofh.it>
[not found] ` <9OlqL-2xG-3@gated-at.bofh.it>
[not found] ` <9Orda-3ub-45@gated-at.bofh.it>
2008-01-24 17:32 ` Bodo Eggert
2008-01-24 22:07 ` Andreas Dilger
2008-01-24 23:08 ` Adrian Bunk
2008-01-24 23:40 ` Theodore Tso
2008-01-25 0:25 ` Zan Lynx
2008-01-25 11:09 ` Andreas Dilger
2008-01-26 0:55 ` Zan Lynx
2008-01-26 11:56 ` KOSAKI Motohiro
2008-01-26 12:32 ` KOSAKI Motohiro
[not found] <alpine.LSU.0.999.0801252338460.26260@be1.lrz>
2008-01-26 1:55 ` Bryan Henderson
2008-01-26 13:21 ` Theodore Tso
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