Dan Naumov wrote:

I am having a slight issue (and judging by Google results, similar
issues have been seen by other FreeBSD and Solaris/OpenSolaris users)
with writes choking the read IO. The issue I am having is described
pretty well here:
http://opensolaris.org/jive/thread.jspa?threadID=106453 It seems that
under heavy write load, ZFS likes to aggregate a really huge amount of
data before actually writing it to disks, resulting in sudden 10+
second stalls where it frantically tries to commit everything,
completely choking read IO in the process and sometimes even the
network (with a large enough write to a mirror pool using DD, I can
cause my SSH sessions to drop dead, without actually running out of
RAM. As soon as the data is committed, I can reconnect back).

Mostly a wild guess, but can you test if this patch will help with choking your network and ssh:



You can then fiddle with the vfs.zfs.zio_worker_threads_count loader tunable to see if it helps more.

freebsd-questions@freebsd.org mailing list
To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"

Reply via email to