From: pg@mdraid.list.sabi.co.UK (Peter Grandi)
To: Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: Linux RAID with btrfs stuck and consume 100 % CPU
Date: Thu, 20 Aug 2020 00:11:49 +0100 [thread overview]
Message-ID: <24381.45493.238720.540436@cyme.ty.sabi.co.uk> (raw)
In-Reply-To: <CAJCQCtTQN60V=DEkNvDedq+usfmFB+SQP2SBezUaSeUjjY46nA@mail.gmail.com>
[...]
> But I do see in the sysrq+w evidence of a Btrfs snapshot
> happening,
There is a known "limitation" with Btrfs and subvolumes and high
CPU usage, especially when there are many (more than a few
dozen) snapshots:
https://btrfs.wiki.kernel.org/index.php/Gotchas#Having_many_subvolumes_can_be_very_slow
> which will result in a flush of the file system. Since the
> mdadm raid journal is on two SSDs which should be fast enough
Are those SSDs expensive "enterprise" class models with
supercapacitor power backup?
> to accept the metadata changes before actually doing the
> flush.
Each metadata change is am "sync" point too.
next prev parent reply other threads:[~2020-08-20 0:18 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 20:47 Linux RAID with btrfs stuck and consume 100 % CPU Vojtech Myslivec
2020-07-22 22:00 ` antlists
2020-07-23 2:08 ` Chris Murphy
[not found] ` <29509e08-e373-b352-d696-fcb9f507a545@xmyslivec.cz>
2020-07-28 20:23 ` Chris Murphy
[not found] ` <695936b4-67a2-c862-9cb6-5545b4ab3c42@xmyslivec.cz>
2020-08-14 20:04 ` Chris Murphy
[not found] ` <2f2f1c21-c81b-55aa-6f77-e2d3f32d32cb@xmyslivec.cz>
2020-08-19 22:58 ` Chris Murphy
2020-08-19 23:11 ` Peter Grandi [this message]
2020-08-26 15:35 ` Vojtech Myslivec
2020-08-26 18:07 ` Chris Murphy
2020-09-16 9:42 ` Vojtech Myslivec
2020-09-17 17:08 ` Chris Murphy
2020-09-17 17:20 ` Chris Murphy
2020-09-17 17:43 ` Chris Murphy
2020-09-23 18:14 ` Vojtech Myslivec
[not found] ` <DBB07C8C-0D83-47DC-9B91-78AD385775E3@snapdragon.cc>
[not found] ` <D3026A55-A7F2-4432-87A8-3E9B2CACE4C2@snapdragon.cc>
[not found] ` <56AD80D0-6853-4E3A-A94C-AD1477D3FDA4@snapdragon.cc>
2021-03-17 15:55 ` Vojtech Myslivec
2020-07-29 21:06 ` Guoqing Jiang
2020-07-29 21:48 ` Chris Murphy
2020-08-12 14:19 ` Vojtech Myslivec
2020-07-30 6:45 ` Song Liu
2020-08-12 13:58 ` Vojtech Myslivec
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