From: "Jorg Bornschein" <jb@capsec.org>
To: "Goldwyn Rodrigues" <rgoldwyn@suse.de>, linux-btrfs@vger.kernel.org
Subject: Re: Very slow balance / btrfs-transaction
Date: Sat, 04 Feb 2017 01:47:46 +0000 [thread overview]
Message-ID: <f9e2b226440e4f6e17e61ce86eecc7eb@88cbed2449cf> (raw)
In-Reply-To: <fce777cb-027f-532b-76ab-24a1e5c2cf7c@suse.de>
February 4, 2017 1:07 AM, "Goldwyn Rodrigues" <rgoldwyn@suse.de> wrote:
> On 02/03/2017 06:30 PM, Jorg Bornschein wrote:
>
>> February 3, 2017 11:26 PM, "Goldwyn Rodrigues" <rgoldwyn@suse.com> wrote:
>>
>> Hi,
>>
>> I'm currently running a balance (without any filters) on a 4 drives raid1 filesystem. The array
>> contains 3 3TB drives and one 6TB drive; I'm running the rebalance because the 6TB drive recently
>> replaced a 2TB drive.
>>
>> I know that balance is not supposed to be a fast operation, but this one is now running for ~6 days
>> and it managed to balance ~18% (754 out of about 4250 chunks balanced (755 considered), 82% left)
>> -- so I expect it to take another ~4 weeks.
>>
>> That seems excessively slow for ~8TiB of data.
>>
>> Is this expected behavior? In case it's not: Is there anything I can do to help debug it?
>>> Do you have quotas enabled?
>>
>> I might have activated it when playing with "snapper" -- I remember using some quota command
>> without knowing what it does.
>>
>> How can I check its active? Shall I just disable it wit "btrfs quota disable"?
>
> To check your quota limits:
> # btrfs qgroup show <mountpoint>
>
> To disable
> # btrfs quota disable <mountpoint>
>
> Yes, please check if disabling quotas makes a difference in execution
> time of btrfs balance.
Quata support was indeed active -- and it warned me that the qroup data was inconsistent.
Disabling quotas had an immediate impact on balance throughput -- it's *much* faster now!
>From a quick glance at iostat I would guess it's at least a factor 100 faster.
Should quota support generally be disabled during balances? Or did I somehow push my fs into a weired state where it triggered a slow-path?
Thanks!
j
next prev parent reply other threads:[~2017-02-04 1:47 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-03 22:13 Very slow balance / btrfs-transaction jb
2017-02-03 23:25 ` Goldwyn Rodrigues
2017-02-04 0:30 ` Jorg Bornschein
2017-02-04 1:07 ` Goldwyn Rodrigues
2017-02-04 1:47 ` Jorg Bornschein [this message]
2017-02-04 2:55 ` Lakshmipathi.G
2017-02-04 8:22 ` Duncan
2017-02-06 1:45 ` Qu Wenruo
2017-02-06 16:09 ` Goldwyn Rodrigues
2017-02-07 0:22 ` Qu Wenruo
2017-02-07 15:55 ` Filipe Manana
2017-02-08 0:39 ` Qu Wenruo
2017-02-08 13:56 ` Filipe Manana
2017-02-09 1:13 ` Qu Wenruo
2017-02-06 9:14 ` Jorg Bornschein
2017-02-06 9:29 ` Qu Wenruo
2017-02-04 20:50 ` Jorg Bornschein
2017-02-04 21:10 ` Kai Krakow
2017-02-06 13:19 ` Austin S. Hemmelgarn
2017-02-07 19:47 ` Kai Krakow
2017-02-07 19:58 ` Austin S. Hemmelgarn
-- strict thread matches above, loose matches on Subject: below --
2017-07-01 14:24 Sidney San Martín
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=f9e2b226440e4f6e17e61ce86eecc7eb@88cbed2449cf \
--to=jb@capsec.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=rgoldwyn@suse.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).