Disk/ZFS activity crash on 11.2-STABLE [SOLVED]

Mike Tancsa mike at sentex.net
Fri Jul 13 19:22:44 UTC 2018

On 7/13/2018 3:10 PM, Jim Long wrote:
> It appears that limiting the ARC size did it.  The 'zfs send -R' was
> able to complete with ARC limited to 50G, and a second run with a 60G
> ARC limit also completed.

Great! I am glad that helped. Its helpful to me too as I have some
systems I am upgrading to RELENG_11 from RELENG_10 soon.  I was aware of
this particular issue, but was worried perhaps your crashes were related
to something else I might run into :)

If you ever have a system with a LOT of small files and directories, a
handy value to tune / keep an eye on is the mix allocated to metadata vs
file data. vfs.zfs.arc_meta_limit.  You can tell when doing things like
"ls" in a directory takes a LONG time to list files. In my case, I had
many directories with 50,000+ files.

Also things like 'zfs list -t snapshot' start to take a long time.


Mike Tancsa, tel +1 519 651 3400 x203
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada

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