Re: Lots of harddrive chatter on after booting with btrfs on root (slow boot)

[George Mitchell <george@chinilu.com>]

Sounds to me like a fragmentation issue.

On 07/20/2013 08:15 AM, Jason Russell wrote:
> Hi,
>
> I've been using btrfs for my root partition for about a month on
> archlinux and recently Ive started using the i3 window manager and
> starting X manually and I now boot to run level 3 (multi-user.target
> for systemd) and Ive noticed that booting archlinux on a btrfs root,
> there is a lot off hdd chatter after the login prompts are displayed,
> which doesnt happen with ext4 on root, so I have done some testing and
> comparisons.
>
> I have stripped down two arch installs, one with btrfs root and one
> with ext4, (same laptop, same hdd) I removed all packages except for
> the base group. On the btrfs root, there is about +- 15 seconds of hdd
> chatter and it takes a long time to log in from the prompts, with the
> ext4 root, the computer is silent after the prompts pop up and login
> is almost instant. The prompts of the two installs pop up at more or
> less the same time (+- 3 seconds) but the login on the btrfs root
> takes muuch longer than the ext4.
>
> Ive also noted that this excessive hdd chatter does not occur
> immediately after a fresh format with arch on btrfs root.
>
> Ive made some deductions/assumptions:
> This only seems to occur with btrfs roots.
> This only happens after some number of reboots OR after the partition
> fills up a little bit.
> Im pretty sure of ruled out everything except for the filesystem.
>
>
> I have just done two clean installs to more thoroughly compare ext4
> and btrfs roots. So far no excessive hdd chatter from btrfs.
>
> I have also seen what I have described on two other computers
> (different hardware entirely) where there is lots of hdd chatter from
> btrfs root, and nothing from ext4.
>
> Here are two threads:
> https://bbs.archlinux.org/viewtopic.php?pid=1117932
> https://bbs.archlinux.org/viewtopic.php?pid=1301684
>
> Any ideas?
>
> Thanks,
>
> --
> Jason Russell
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