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From: Qu Wenruo <>
To: Moritz M <>
Subject: Re: Help needed, server is unresponsive after btrfs balance
Date: Tue, 5 Feb 2019 20:17:50 +0800
Message-ID: <> (raw)
In-Reply-To: <>

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On 2019/2/5 下午7:45, Moritz M wrote:
> Am 2019-02-04 14:55, schrieb Qu Wenruo:
>> On 2019/2/4 下午8:49, Moritz M wrote:
>>>> You're using qgroups, it's known to cause huge performance overhead for
>>>> balance.
>>>> We have upcoming patches to solve it, but it not going to mainline
>>>> before v5.1 kernel.
>>>> So please disable qgroups if you're not using it actively.
>>> Thanks, was not aware that I turned it on. Is
>>> btrfs quota disable /
>>> enough for disabling qgroups?
>> Yep
> Do you have any idea how to validate if the enabled qgroups led to my
> problem?

It's a common fact.

Especially for balance.

In this patch you could see some of the performance difference:

The final fix should make balance only takes 3 seconds for that workload.
Exactly the same with qgroup disabled.

In short, quota enabled, balance takes 20s~2min (depends on the kernel
version), with quota disabled or with all my optimization, it takes 3s.


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      reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-04 11:47 Moritz M
2019-02-04 11:59 ` Qu Wenruo
2019-02-04 12:52   ` Moritz M
     [not found]   ` <>
     [not found]     ` <>
2019-02-05 11:45       ` Moritz M
2019-02-05 12:17         ` Qu Wenruo [this message]

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