Bug#776034: fsck runs in parallel on same physical disk

[Josh Triplett]

On Fri, 23 Jan 2015 07:44:57 +0100 Daniel Pocock <daniel at pocock.pro> wrote:
> I have a server with many LVM logical volumes on top of the same RAID1
> md device on two spindles.
> 
> At boot, fsck appeared to be starting on many of the LVs simultaneously.
> 
> There was a horrendous sound of disk head movement from the server.
> 
> This also makes the whole fsck process slower and therefore the boot
> process is slower.

systemd-fsck is supposed to avoid this.  According to its manpage:

> The file system check for root is performed before the other file
> systems. Other file systems may be checked in parallel, except when
> they are one the same rotating disk.

Does your LVM setup provide the correct value for "rotational"?  What
does the following command say:

sudo find /sys -name 'rotational' -exec head {} +

- Josh Triplett