From: Andreas Dilger <adilger@sun.com>
Subject: Re: [PATCH] default max mount count to unused
Date: Fri, 22 Jan 2010 01:09:13 -0700
Message-ID: <4B7FFE9D-F110-408D-B432-7D20AEBD4689@sun.com>
References: <4B5785A5.2010505@redhat.com> <20100122012929.GA21263@thunk.org>
 <4B591D80.6010309@redhat.com>
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Cc: tytso@mit.edu, ext4 development <linux-ext4@vger.kernel.org>,
	Bill Nottingham <notting@redhat.com>
To: Eric Sandeen <sandeen@redhat.com>
In-reply-to: <4B591D80.6010309@redhat.com>
Sender: linux-ext4-owner@vger.kernel.org

On 2010-01-21, at 20:37, Eric Sandeen wrote:
> That sounds fine, as do mke2fs.conf hooks, as does a nice shipped  
> script
> to do background checking of snapshots.
>
> But I still don't know why "You mounted your fs 20 times" is a good
> proxy for "you had better check for corruption now."  Have we so
> little faith?  :)


I've thought for quite a while that 20 mounts is too often, but I'm  
reluctant to turn it off completely.  I wouldn't object to increasing  
it to 60 or 80.

At one time there was a patch that checked the state of the filesystem  
at mount time and only incremented only 1/5 of the time (randomly) if  
it was unmounted cleanly (not dirty, or not in recovery), but every  
time if it crashed.  The reasoning was that systems which crashed are  
more likely to have memory corruption or software bugs, and ones that  
shut down cleanly are less likely to have such problems.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.