From: Brandon Heisner <brandonh@wolfram.com>
To: linux-btrfs@vger.kernel.org
Subject: btrfs metadata has reserved 1T of extra space and balances don't reclaim it
Date: Tue, 28 Sep 2021 21:23:01 -0500 (CDT) [thread overview]
Message-ID: <70668781.1658599.1632882181840.JavaMail.zimbra@wolfram.com> (raw)
I have a server running CentOS 7 on 4.9.5-1.el7.elrepo.x86_64 #1 SMP Fri Jan 20 11:34:13 EST 2017 x86_64 x86_64 x86_64 GNU/Linux. It is version locked to that kernel. The metadata has reserved a full 1T of disk space, while only using ~38G. I've tried to balance the metadata to reclaim that so it can be used for data, but it doesn't work and gives no errors. It just says it balanced the chunks but the size doesn't change. The metadata total is still growing as well, as it used to be 1.04 and now it is 1.08 with only about 10G more of metadata used. I've tried doing balances up to 70 or 80 musage I think, and the total metadata does not decrease. I've done so many attempts at balancing, I've probably tried to move 300 chunks or more. None have resulted in any change to the metadata total like they do on other servers running btrfs. I first started with very low musage, like 10 and then increased it by 10 to try to see if that would balance any chunks out, but with no success.
# /sbin/btrfs balance start -musage=60 -mlimit=30 /opt/zimbra
Done, had to relocate 30 out of 2127 chunks
I can do that command over and over again, or increase the mlimit, and it doesn't change the metadata total ever.
# btrfs fi show /opt/zimbra/
Label: 'Data' uuid: ece150db-5817-4704-9e84-80f7d8a3b1da
Total devices 4 FS bytes used 1.48TiB
devid 1 size 1.46TiB used 1.38TiB path /dev/sde
devid 2 size 1.46TiB used 1.38TiB path /dev/sdf
devid 3 size 1.46TiB used 1.38TiB path /dev/sdg
devid 4 size 1.46TiB used 1.38TiB path /dev/sdh
# btrfs fi df /opt/zimbra/
Data, RAID10: total=1.69TiB, used=1.45TiB
System, RAID10: total=64.00MiB, used=640.00KiB
Metadata, RAID10: total=1.08TiB, used=37.69GiB
GlobalReserve, single: total=512.00MiB, used=0.00B
# btrfs fi us /opt/zimbra/ -T
Overall:
Device size: 5.82TiB
Device allocated: 5.54TiB
Device unallocated: 291.54GiB
Device missing: 0.00B
Used: 2.96TiB
Free (estimated): 396.36GiB (min: 396.36GiB)
Data ratio: 2.00
Metadata ratio: 2.00
Global reserve: 512.00MiB (used: 0.00B)
Data Metadata System
Id Path RAID10 RAID10 RAID10 Unallocated
-- -------- --------- --------- --------- -----------
1 /dev/sde 432.75GiB 276.00GiB 16.00MiB 781.65GiB
2 /dev/sdf 432.75GiB 276.00GiB 16.00MiB 781.65GiB
3 /dev/sdg 432.75GiB 276.00GiB 16.00MiB 781.65GiB
4 /dev/sdh 432.75GiB 276.00GiB 16.00MiB 781.65GiB
-- -------- --------- --------- --------- -----------
Total 1.69TiB 1.08TiB 64.00MiB 3.05TiB
Used 1.45TiB 37.69GiB 640.00KiB
--
Brandon Heisner
System Administrator
Wolfram Research
next reply other threads:[~2021-09-29 2:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-29 2:23 Brandon Heisner [this message]
2021-09-29 7:23 ` btrfs metadata has reserved 1T of extra space and balances don't reclaim it Forza
2021-09-29 14:34 ` Brandon Heisner
2021-10-03 11:26 ` Forza
2021-10-03 18:21 ` Zygo Blaxell
2021-09-29 8:22 ` Qu Wenruo
2021-09-29 15:18 ` Andrea Gelmini
2021-09-29 16:39 ` Forza
2021-09-29 18:55 ` Andrea Gelmini
2021-09-29 17:31 ` Zygo Blaxell
2021-10-01 7:49 ` Brandon Heisner
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