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: https://patchwork.kernel.org/cover/10725589/ 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. Thanks, Qu
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