linux-ext4 - Re: [PATCH] default max mount count to unused

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Message-id: <F348497E-C9B1-49D3-920B-5AF98CBDDD98@sun.com>
Date:	Thu, 21 Jan 2010 17:22:55 -0700
From:	Andreas Dilger <adilger@....com>
To:	Eric Sandeen <sandeen@...hat.com>
Cc:	ext4 development <linux-ext4@...r.kernel.org>,
	Bill Nottingham <notting@...hat.com>,
	Alasdair G Kergon <agk@...hat.com>,
	LVM Mailing List <linux-lvm@...hat.com>,
	"Theodore Ts'o" <tytso@....edu>
Subject: Re: [PATCH] default max mount count to unused

On 2010-01-20, at 15:37, Eric Sandeen wrote:
> From: Bill Nottingham <notting@...hat.com>
>
> Anaconda has been setting the max mount count on the root fs
> to -1 (unused) for ages.
>
> I (Eric) tend to agree that using mount count as a proxy for potential
> for corruption seems odd.  And waiting for fsck on a reboot just  
> because
> it's number 20 (or so) is painful.  Can we just turn it off by  
> default?
>
> I wouldn't mind killing the periodic check as well, but consider
> this a trial balloon.  :)

Rather than disabling the mount-count check, it would make a lot of  
sense to rather enable background checking via LVM snapshots, as  
described in:

https://www.redhat.com/archives/ext3-users/2008-February/msg00004.html

I've attached an updated version of this script and its config file.   
I've run a fair amount of testing on the script and it seems to do the  
right thing, and started running it from my /etc/cron.weekly to give  
it some further ongoing testing.

Since virtually all new distros use LVM devices, this makes a lot of  
sense to configure by default, rather than leaving filesystems to bit- 
rot in silence by turning off the periodic checking.  This also avoids  
the "all devices check after 6 months" problem for servers that reboot  
only rarely, because the filesystems get a periodic check and reset  
the check timestamp/interval so they will never need checking at boot  
time unless there is an error.

Alasdair, any chance you can include this script into the LVM package?

Ted, this should really be added to e2fsprogs, and the e2croncheck  
script removed.  The existing e2croncheck script is broken in a number  
of ways (e.g. the force check timestamp 19000101 is invalid, the email  
reporting doesn't work because "$RPT-EMAIL" is never set) and is less  
functional in other ways (it doesn't remove stale snapshots in case of  
an interrupted script, it doesn't check multiple LVs, etc).

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

Download attachment "lvcheck" of type "application/octet-stream" (10833 bytes)

Download attachment "lvcheck.conf" of type "application/octet-stream" (1242 bytes)