From: Stan Hoeppner <stan@hardwarefreak.com>
To: xfs@oss.sgi.com
Subject: Re: Insane file system overhead on large volume
Date: Fri, 27 Jan 2012 13:08:27 -0600 [thread overview]
Message-ID: <4F22F62B.2090506@hardwarefreak.com> (raw)
In-Reply-To: <CAEBWcAT2zfDskgDjFr0KcnfsT2A65r04AM1cv2-TfnNJTB1__Q@mail.gmail.com>
On 1/27/2012 1:50 AM, Manny wrote:
> Hi there,
>
> I'm not sure if this is intended behavior, but I was a bit stumped
> when I formatted a 30TB volume (12x3TB minus 2x3TB for parity in RAID
> 6) with XFS and noticed that there were only 22 TB left. I just called
> mkfs.xfs with default parameters - except for swith and sunit which
> match the RAID setup.
>
> Is it normal that I lost 8TB just for the file system? That's almost
> 30% of the volume. Should I set the block size higher? Or should I
> increase the number of allocation groups? Would that make a
> difference? Whats the preferred method for handling such large
> volumes?
Maybe you simply assigned 2 spares and forgot, so you actually only have
10 RAID6 disks with 8 disks worth of stripe, equaling 24 TB, or 21.8
TiB. 21.8 TiB matches up pretty closely with your 22 TB, so this
scenario seems pretty plausible, dare I say likely.
If this is the case you'll want to reformat the 10 disk RAID6 with the
proper sunit/swidth values.
--
Stan
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prev parent reply other threads:[~2012-01-27 19:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-27 7:50 Insane file system overhead on large volume Manny
2012-01-27 10:44 ` Christoph Hellwig
2012-01-27 19:15 ` Manny
2012-01-27 18:21 ` Eric Sandeen
2012-01-28 14:55 ` Martin Steigerwald
2012-01-28 15:35 ` Eric Sandeen
2012-01-28 16:05 ` Christoph Hellwig
2012-01-28 16:07 ` Eric Sandeen
2012-01-28 16:23 ` Martin Steigerwald
2012-01-29 22:18 ` Dave Chinner
2012-01-27 19:08 ` Stan Hoeppner [this message]
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