From: Dave Chinner <david@fromorbit.com>
To: Martin Steigerwald <Martin@lichtvoll.de>
Cc: Pascal <pa5ca1@gmx.de>, xfs@oss.sgi.com
Subject: Re: Maximum file system size of XFS?
Date: Tue, 12 Mar 2013 09:19:36 +1100 [thread overview]
Message-ID: <20130311221936.GD21651@dastard> (raw)
In-Reply-To: <201303112257.00798.Martin@lichtvoll.de>
On Mon, Mar 11, 2013 at 10:57:00PM +0100, Martin Steigerwald wrote:
> Am Montag, 11. März 2013 schrieb Martin Steigerwald:
> > 2) Create a insanely big sparse file
> >
> > merkaba:~> truncate -s1E /mnt/zeit/evenmorecrazy.img
> > merkaba:~> ls -lh /mnt/zeit/evenmorecrazy.img
> > -rw-r--r-- 1 root root 1,0E Mär 11 22:37 /mnt/zeit/evenmorecrazy.img
> >
> > (No, this won´t work with Ext4.)
>
> Okay, you can´t go beyond 8 EiB for a single file which is about what I have
> read somewhere:
Right - file size offsets max out at 2^63 bytes.
....
> merkaba:/mnt/zeit#5> vgcreate --physicalextentsize 4G justinsane /dev/loop0
> /dev/loop1
> Volume group "justinsane" successfully created
>
> merkaba:/mnt/zeit> vgs
> VG #PV #LV #SN Attr VSize VFree
> justinsane 2 0 0 wz--n- 14,00e 14,00e
> merkaba 1 4 0 wz--n- 278,99g 4,85g
> merkaba:/mnt/zeit>
....
> Enough insanity for today :)
>
> I won´t mkfs.xfs on it, the 20 GiB of the just filesystem wouldn´t be
> enough.
Right - I did a mkfs.xfs on a (8EB - 1GB) file a couple of days ago
just to check it worked. I killed it after a short while, because I
didn't feel like needlessly subjecting the SSDs the file was
physically located on to the 25 million sparse sector sized writes
needed for mkfs to complete.
And you can double that number of writes needed for a 16EB
filesystem to be initialised by mkfs. So, theory be damned, even
mkfs.xfs doesn't scale to supporting exabyte filesystems...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2013-03-11 22:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-09 20:51 Maximum file system size of XFS? Pascal
2013-03-09 22:29 ` Ric Wheeler
2013-03-09 22:39 ` Pascal
2013-03-10 1:10 ` Eric Sandeen
2013-03-10 7:54 ` Stan Hoeppner
2013-03-11 11:02 ` Stan Hoeppner
2013-03-11 16:15 ` Hans-Peter Jansen
2013-03-11 16:22 ` Emmanuel Florac
2013-03-11 1:55 ` Dave Chinner
2013-03-11 21:45 ` Martin Steigerwald
2013-03-11 21:57 ` Martin Steigerwald
2013-03-11 22:01 ` Martin Steigerwald
2013-03-11 22:04 ` Martin Steigerwald
2013-03-20 18:26 ` Pascal
2013-03-11 22:19 ` Dave Chinner [this message]
2013-03-11 22:10 ` Martin Steigerwald
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