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Message-ID: <48B7ED40.6020508@redhat.com>
Date: Fri, 29 Aug 2008 07:36:16 -0500
From: Eric Sandeen <sandeen@...hat.com>
To: ext4 development <linux-ext4@...r.kernel.org>
CC: Ric Wheeler <rwheeler@...hat.com>
Subject: Re: Do we need dump for ext4?
Eric Sandeen wrote:
> I was talking to Ric about dump benchmarks, and he was of the impression
> that dump may not be used that often anymore, at least in the
> enterprise. (Ric, hope I'm paraphrasing correctly)
>
> Undaunted :) I ran off and tested an artificial backup scenario:
>
> * Untar a kernel tree into 128 different top level dirs
> * Make a level 0 backup
> * Untar a kernel tree into 128 MORE different top level dirs
> * Make a level 1 backup
>
> 128 kernel trees uses about 6.5M inodes, and about 80G of space.
>
> I tested ext3 with dump; ext4 with tar, and xfs with xfsdump.
>
> for ext3:
> dump -1 -u -f $DUMPDIR/dump1 $DATADIR
>
> for ext4:
> tar --atime-preserve --xattr --after-date=$DUMPDIR/dump0.tar -cf
> $DUMPDIR/dump1.tar $DATADIR
>
> for xfs:
> xfsdump -F -l 1 -f $DUMPDIR/dump0 $DATADIR
>
> DUMPDIR and DATADIR were 2 partitions on the same (fast hardware) lun.
>
> Results:
at Ric & hch's request here is tar on the other fs's as well, re-sorted
by level 0 dump time. I put acp into the mix as well.
Oh, and this time I remembered to set the elevator to something sane
(noop) for this storage, oops (was cfq last time)
Also, this time the dup/tar/acp was written to /dev/null rather than
another filesystem. Interesting how routing to /dev/null alone changed
the ranking quite a bit.
level0 level1
====== ======
ext4-acp 12m22s ------
ext3-acp 14m11s ------
ext4-tar 18m24s 34m56s
ext3-dump 19m30s 35m30s
xfs-dump 20m07s 40m24s
ext3-tar 21m16s 42m41s
xfs-tar 21m19s 46m13s
xfs-acp 29m38s ------
-Eric
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