Andrew Snow andrew at modulus.org
Tue Sep 30 01:41:47 UTC 2008

Matthew Dillon wrote:
> It can take 6 hours to fsck a full 1TB HD.  It can
>     take over a day to fsck larger setups.  Putting in a few sleeps here
>     and there just makes the run time even longer and perpetuates the pain.

We have a box with millions of files spread over 2TB, on a 16 disk RAID.
  Foreground fsck takes almost 8 hours, so background fsck, which takes
almost 24 hours or more, is my only option when I want to bring the box
back online quickly.   And UFS Snapshots are so slow as to be completely

I've now converted the volume to ZFS, and am now enjoying instant boot
time and higher speed I/O under heavy load, at the expense of memory

>     My recommendation?  Default UFS back to a synchronous fsck and stop
>     treating ZFS (your only real alternative) as being so ultra-alpha that
>     it shouldn't be used.

Completely agree.  ZFS is the way of the future for FreeBSD.  In my
latest testing, the memory problems are now under control, there is just
stability problems with random lockups after days of heavy load unless I
turn off ZIL.  So its nearly there.

If only ZFS also supported a network distributed mode.  Or can we
convince you to port Hammer to FreeBSD? :-)

- Andrew

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