fsck parallel check

[Rodney W. Grimes]

> can it be changed?

It *could* be changed, but the more important question is *should*
it be changed.  See below.

> fsck checks in sequence all filesystems with 6-th field in /etc/fstab 
> equal 1, and in parallel all with 6-th field equal 2 but one process per 
> disk.
> 
> This is right if you have magnetic disks. checking 2 partitions in 
> parallel on one physical disk is bad idea.
> 
> But it is very good idea to do this on SSD with multiple partitions.

Why do you state that?

>From my perspective it is more that one thread is "good enough":
fsck should be I/O bound, more threads on a single ssd should just
lead to I/O queue building and no net reduction in time to complete.

Do you have some data that contridicts that?

> 
> Can it be changed ?

See above.

> 
> If not - i can write a fix for this (option settable in fstab).
-- 
Rod Grimes                                                 rgrimes at freebsd.org