Re: Btrfs might be gradually slowing the boot process

[Kai Krakow <hurikhan77+btrfs@gmail.com>]

yzb3@wp.pl <yzb3@wp.pl> schrieb:

> I recently noticed that my boot has become slower - it took around 29s,
> while at the beginning it was ~6s. I thought it was an issue with systemd,
> because it failed to properly indicate at which stage the slowdown
> occurred and how long it took. I rolled back to a pretty fresh root
> subvolume and the boot was fast again. However, after several reboots it
> started lagging again (10s? preposterous!). I decided to try the
> *clear_cache* mount option; it was only a guess, but it did speed the boot
> to the proper ~6s.
> 
> The question is - why? My filesystem is really small - I see no reason for
> a 5x boot slowdown. Is this a known issue? I will be glad to give any
> additional details about my fs.

I'm using a similar setup (although my btrfs rootfs is a 3 disk array and is 
more or less huge) and I didn't see such a vast boot slowdown. Did you check 
that systemd is actually using the readahead services which will relocate 
and defragment your boot files automatically?

HTH
Kai