> The system has 6GB of RAM and a 10GB swap partition. I added a 30GB
> swap file but this hasn't helped.

ZFS doesn't use swap for the ARC (it's wired aka unswappable memory).  And
ZFS uses the ARC for dedupe support.

You will need to find a lot of extra RAM to stuff into that machine in
order for it to boot correctly, load the dedeupe tables into ARC, process
the intent log, and then import the pool.

And, you'll need that extra RAM in order to destroy the ZFS filesystem that
has dedupe enabled.

Basically, your DDT (dedupe table) is running you out of ARC space and
livelocking (or is it deadlocking, never can keep those terms straight) the

You can remove the RAM once you have things working again.  Just don't
re-enable dedupe until you have at least 16 GB of RAM in the box that can
be dedicated to ZFS.  And be sure to add a cache device to the pool.

I just went through something similar with an 8 GB ZFS box (RAM is on
order, but purchasing dept ordered from wrong supplier so we're stuck
waiting for it to arrive) where I tried to destroy dedupe'd filesystem.
 Exact same results as you.  Stole RAM out of a different server
temporarily to get things working on this box again.

> # sysctl hw.physmem
> hw.physmem: 6363394048
> # sysctl vfs.zfs.arc_max
> vfs.zfs.arc_max: 5045088256
> (I lowered arc_max to 1GB but hasn't helped)


Freddie Cash
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