From mboxrd@z Thu Jan  1 00:00:00 1970
From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=)
Subject: Re: Performance issues with /gnu/store in virtual machines
Date: Tue, 22 Aug 2017 16:33:12 +0200
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References: <20170817210547.3fafde57@cbaines.net> <87shgj7vz4.fsf@gnu.org>
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To: =?utf-8?B?5a6L5paH5q2m?= <iyzsong@member.fsf.org>
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iyzsong@member.fsf.org (=E5=AE=8B=E6=96=87=E6=AD=A6) skribis:

> ludo@gnu.org (Ludovic Court=C3=A8s) writes:
>
>> Hi Chris,
>>
>> Christopher Baines <mail@cbaines.net> skribis:
>>
>>>   1.13    0.000019           0      3853           openat
>>
>> [...]
>>
>>>  13.56    0.193014          50      3853           openat
>>
>> So openat(2) is 4 orders of magnitude slower in the VM, which is a
>> problem.
>>
>> I guess a large part of that is due to the fact that VM created with
>> =E2=80=98guix system vm=E2=80=99 use unionfs as their root file system, =
which is a FUSE
>> thing (see the =E2=80=9Cvolatile=E2=80=9D options in (gnu system vm), (g=
nu system
>> linux-initrd), and (gnu build linux-boot).)  I=E2=80=99m not sure how we=
 could
>> avoid it.
>
> We might switch to the linux kernel's bultin overlayfs, which should be
> faster.
>
> https://wiki.archlinux.org/index.php/Overlay_filesystem

Good point, we should probably do that.

Ludo=E2=80=99.