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From: Roman Mamedov <rm@romanrm.net>
To: Justin Brown <otakujunction@gmail.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: Help with space
Date: Fri, 28 Feb 2014 10:34:36 +0600	[thread overview]
Message-ID: <20140228103436.2dfd2669@natsu> (raw)
In-Reply-To: <CAAmRLYx1L=o7a2PMSAiJbr7qH_JiuYG2-ncHG-mHLyLcM3Z-GQ@mail.gmail.com>

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On Thu, 27 Feb 2014 12:19:05 -0600
Justin Brown <otakujunction@gmail.com> wrote:

> I've a 18 tera hardware raid 5 (areca ARC-1170 w/ 8 3 gig drives) in

Do you sleep well at night knowing that if one disk fails, you end up with
basically a RAID0 of 7x3TB disks? And that if 2nd one encounters unreadable
sector during rebuild, you lost your data? RAID5 actually stopped working 5
years ago, apparently you didn't get the memo. :)
http://hardware.slashdot.org/story/08/10/21/2126252/why-raid-5-stops-working-in-2009

> need of help.  Disk usage (du) shows 13 tera allocated yet strangely
> enough df shows approx. 780 gigs are free.  It seems, somehow, btrfs
> has eaten roughly 4 tera internally.  I've run a scrub and a balance
> usage=5 with no success, in fact I lost about 20 gigs after the

Did you run balance with "-dusage=5" or "-musage=5"? Or both?
What is the output of the balance command?

> terra:/var/lib/nobody/fs/ubfterra # btrfs fi df .
> Data, single: total=17.58TiB, used=17.57TiB
> System, DUP: total=8.00MiB, used=1.93MiB
> System, single: total=4.00MiB, used=0.00
> Metadata, DUP: total=392.00GiB, used=33.50GiB
                       ^^^^^^^^^

If you'd use "-musage=5", I think this metadata reserve should have been
shrunk, and you'd gain a lot more free space.

But then as others mentioned it may be risky to use this FS on 32-bit at all,
so I'd suggest trying anything else only after you reboot into a 64-bit kernel.

-- 
With respect,
Roman

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  parent reply	other threads:[~2014-02-28  4:34 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-27 18:19 Help with space Justin Brown
2014-02-27 19:27 ` Chris Murphy
2014-02-27 19:51   ` Chris Murphy
2014-02-27 20:49     ` otakujunction
2014-02-27 21:11       ` Chris Murphy
2014-02-28  0:12         ` Dave Chinner
2014-02-28  0:27           ` Chris Murphy
2014-02-28  4:21             ` Dave Chinner
2014-02-28  5:49               ` Chris Murphy
2014-02-28  4:34 ` Roman Mamedov [this message]
2014-02-28  7:27   ` Duncan
2014-02-28  7:37     ` Roman Mamedov
2014-02-28  7:46     ` Justin Brown
2014-05-01  1:52   ` Russell Coker
2014-05-01  5:33     ` Duncan
2014-05-02  1:48       ` Russell Coker
2014-05-02  8:23         ` Duncan
2014-05-02  9:28           ` Brendan Hide
2014-05-02 19:21           ` Chris Murphy
2014-05-02 21:08             ` Hugo Mills
2014-05-02 22:33               ` Chris Murphy
2014-05-03 16:31             ` Austin S Hemmelgarn
2014-05-03 19:09               ` Chris Murphy
2014-05-03 20:52                 ` Austin S Hemmelgarn
2014-05-03 23:16                 ` Chris Murphy
2014-02-28  6:13 ` Chris Murphy
2014-02-28  6:26   ` Chris Murphy
2014-02-28  7:39     ` Justin Brown

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