Differences in memory handling on systems with/out cache drives
Karli.Sjoberg at slu.se
Fri Nov 7 08:20:31 UTC 2014
On Wed, 2014-11-05 at 16:36 +0100, Erik Stian Tefre wrote:
> On 05. nov. 2014 09:53, Karli Sjöberg wrote:
> > On Wed, 2014-11-05 at 08:44 +0000, Karli Sjöberg wrote:
> >> Hey all!
> >> Still investigating the intermittent lockups we are experiencing on our
> >> storage systems and have started to compare memory graphs from our
> >> Graphite monitoring system. What´s interesting about two of our systems
> >> is that they both have the same amount of RAM; 32 GB. But on one of
> >> them, I have "zpool remove"'d the cache drives from the pool and have
> >> been able to study how different their memory graphs now look like.
> >> Also worth noting is that the cache-less system nearly haven´t swapped
> >> at all (1112K) since the last stall 20 days ago, while the other system
> >> has swapped 78 MB during it´s 48 days of uptime.
> >> I´ve attached both screenshots from the two systems, with- and without
> >> cache drives, displaying a period of 12 hours.
> >> What´s most notable are the characteristic cuts that happen on the
> >> cache-less system when ZFS goes in and evicts blocks from ARC that shows
> >> as a decrease in "wired" and increase in "free", that just doesn´t
> >> happen/looks different in the system with cache drive configured in the
> >> pool.
> >> What´s your take on this? Are we hitting bug: 187594 perhaps? How can we
> >> know?
> Take a look at the recent thread on freebsd-stable@, subject "ARC size
> limit". Possibly related issues have been patched in stable/10, the
> mailing list thread includes a patch for releng/10.1.
Thanks! I looked at it and saw that that´s one that´s going to be used
for 10.1 and the patch referred to is the same as the one developed
for bug 187594, which still has status "In Discussion". The patch
really should be verified by OP there before issue is _really_ declared
Do you have any chance of verifying this, as you were the one that first
reported about it? I would personally feel so much better knowing we can
finally rid ourselves of this menace in 10.1:)
Med Vänliga Hälsningar
Swedish University of Agricultural Sciences Box 7079 (Visiting Address
S-750 07 Uppsala, Sweden
Phone: +46-(0)18-67 15 66
karli.sjoberg at slu.se
More information about the freebsd-fs