ZFS and Wired memory, again

[Volodymyr Kostyrko]

28.02.2014 13:47, Matthias Gamsjager wrote:
>
>
>     +1 from me, FreeBSD 10, uma=0
>
>     52 processes:  2 running, 49 sleeping, 1 zombie
>     CPU:  0.0% user,  0.0% nice,  0.0% system,  0.4% interrupt, 99.6% idle
>     Mem: 31M Active, 16K Inact, 3352M Wired, 17M Cache, 48M Free
>     ARC: 1838M Total, 110M MFU, 18M MRU, 548K Anon, 1876M Header, 75M Other
>     Swap: 4096M Total, 126M Used, 3969M Free, 3% Inuse
>
>     Machine is plain dead. Running database or squid or anything causes
>     excessive swapping. This is the state when I disabled all payload,
>     with everything started swap goes to 500M and machine is burning disks.
>
>
> I wonder do you use any zfs tuning? Like max arc size? Wonder if setting
> that to a reasonable amount would help.

The previous sample was taken without any tunables. After that I enabled 
vfs.zfs.zio.use_uma in /boot/loader.conf and now everything looks like:

103 processes: 1 running, 101 sleeping, 1 zombie
CPU:  0.0% user,  0.0% nice,  1.2% system,  2.0% interrupt, 96.9% idle
Mem: 137M Active, 13M Inact, 3176M Wired, 14M Cache, 111M Free
ARC: 2026M Total, 781M MFU, 72M MRU, 414K Anon, 1221M Header, 98M Other
Swap: 4096M Total, 263M Used, 3833M Free, 6% Inuse

Currently wired memory grows and pushes inactive to swap. Sometimes 
wired memory retracts freeing 100MB or so. Machine is in working state 
currently.

The major changes are:

* less wired;
* more arc;
* a lot of header memory but less then before, I wonder whether it only 
grows or retracts...

I'm also thinking about trying a patch to l2arc as this system uses 
external l2 cache.

-- 
Sphinx of black quartz, judge my vow.