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From: Dave Chinner <david@fromorbit.com>
To: Linda Walsh <xfs@tlinx.org>
Cc: xfs-oss <xfs@oss.sgi.com>
Subject: Re: xfs_freeze same as umount?   How is that helpful?
Date: Fri, 5 Oct 2012 09:32:04 +1000	[thread overview]
Message-ID: <20121004233204.GB23644@dastard> (raw)
In-Reply-To: <506E1025.8050605@tlinx.org>

On Thu, Oct 04, 2012 at 03:39:33PM -0700, Linda Walsh wrote:
> Greg Freemyer wrote:
> >Conceptually it is typically:
> >- quiesce system
> ----
> 	Um... it seems that this is equivalent to being
> able to umount the disk?

NO, it's not. freeze intentionally leaves the log dirty, whereas
unmount leaves it clean.

> When I tried xfs_freeze / fs_freeze got fs-busy -- same as I would
> if I tried to umount it.

Of course - it's got to write all the dirty data andmetadata in
memory to disk. Freeze is about providing a stable, consistent disk
image of the filesystem, so it must flush dirty objects from memory
to disk to provide that.

> I thought the point of xfs_freeze was to allow it to be brought to
> a consistent state without unmounting it?

Exactly.

> Coincidentally, after trying a few freezes, the system froze.

Entirely possible if you froze the root filesystem and something you
rely on tried to write to the filesystem.

Anyway, a one-line "it froze" report doesn't tell us anything about
the problem you saw. So:

http://xfs.org/index.php/XFS_FAQ#Q:_What_information_should_I_include_when_reporting_a_problem.3F

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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  reply	other threads:[~2012-10-04 23:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-04 15:30 get filename->inode mappings in bulk for a live fs? Linda Walsh
2012-10-04 18:01 ` Greg Freemyer
2012-10-04 18:29   ` Linda Walsh
2012-10-04 18:59     ` Greg Freemyer
2012-10-04 22:39   ` xfs_freeze same as umount? How is that helpful? Linda Walsh
2012-10-04 23:32     ` Dave Chinner [this message]
2012-10-05  0:10       ` Linda Walsh
2012-10-05  0:36         ` Dave Chinner
2012-10-04 22:49 ` get filename->inode mappings in bulk for a live fs? Dave Chinner

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