Linux – How to configure CONFIG_DEFAULT_RELATIME to disable relatime

configurationfilesystemskernellinux

Since linux 2.6.30, filesystems are mounted with "relatime" by default. In this discussion, Ingo Molnar says he has added the CONFIG_DEFAULT_RELATIME kernel option, which:

makes 'norelatime' the default for all mounts without an extra kernel
boot option.

I don't really get it, I wonder if that means that without CONFIG_DEFAULT_RELATIME in .config, a kernel will not use relatime as a default mount option?

How can one enable or disable CONFIG_DEFAULT_RELATIME in make menuconfig? (I don't find anything related to relatime.)

And finally, I can't even find CONFIG_DEFAULT_RELATIME in the kernel sources.

Can someone enlighten me?

Best Answer

Ingo Molnar proposed a patch, but this patch wasn't accepted into the kernel tree. Linus Torvalds made relatime the default setting in 2.6.30, unconditionally, and this is still true in 3.0. If you want relatime to default off in the kernel, you need to apply Ingo Molnar's patch in your copy of the source.

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When was `relatime` made the default

I remember the change, but couldn't remember the date. It seems that it was back in 2007. According to the article, relatime was available in 2.6.20, and it became the default option a few versions after that ~~(2.6.24)~~ maybe.

Edit: man mount /relatime says 2.6.30.

From ChangeLog-2.6.30:

commit 0a1c01c9477602ee8b44548a9405b2c1d587b5a2
Author: Matthew Garrett <mjg@redhat.com>
Date:   Thu Mar 26 17:53:14 2009 +0000

Make relatime default

Change the default behaviour of the kernel to use relatime for all
filesystems. This can be overridden with the "strictatime" mount
option.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

NFS Automounting – Autofs Timeout Settings for Unreliable Servers

Using any mount system, you want to avoid situations where Nautilus lists the directory containing a mount that may or not be mounted. So, with autofs, don't create mounts in, for instance, /nfs. If you do, when you use Nautilus to list the 'File System' it will try to create whatever mounts should exist in /nfs, and if those mount attempts fail it takes minutes to give up.

So what I did was change auto.master to create the mounts in /nfs/mnt.

This fixed the problem for me. I only get a long delay if I try to list the contents of /nfs/mnt, which I can easily avoid.

Best Answer

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When was `relatime` made the default

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