ZFS and Wired memory, again

Mark Felder feld at FreeBSD.org
Fri Feb 28 19:35:33 UTC 2014


On Fri, Feb 28, 2014, at 13:11, Adam Vande More wrote:
> On Fri, Feb 28, 2014 at 12:53 PM, Anton Sayetsky <vsjcfm at gmail.com>
> wrote:
> 
> > 2014-02-28 20:42 GMT+02:00 Larry Rosenman <ler at lerctr.org>:
> > > On 2014-02-28 12:31, Anton Sayetsky wrote:
> > >>
> > >> 2014-02-28 13:47 GMT+02:00 Matthias Gamsjager <mgamsjager at gmail.com>:
> > >>>>>
> > >>>>>
> > >>>>
> > >>>> +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.
> > >>
> > >> Please read carefully my first message. No any tuning (configs
> > >> posted), and problem is not that ZFS uses big amount of memory. I'm
> > >> experiencing exactly one problem - Wired mem is significantly larger
> > >> than ARC.
> > >> E.g. if my ARC size is 2048M, I'm expecting that Wired will not
> > >> consume more than ARC+~150M.
> > >> _______________________________________________
> > >> freebsd-fs at freebsd.org mailing list
> > >> http://lists.freebsd.org/mailman/listinfo/freebsd-fs
> > >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe at freebsd.org"
> > >
> > > Other pieces of the system used wired memory......
> > >
> > > Have you investigated that as well?
> > And again - this has detailed explanation in the first letter. In short:
> > 1. I've booted the system without any memory hungry services (only
> > basic like cron, powerd). Wired is 95M, ARC is 25M.
> > 2. Then I started reading ZFS pool (tar cpf /dev/null
> > /pool/mountpoint). ARC - 2048M, Wired -  ~2800M.
> > WTF? Who eats more than 700M of kernel memory? Do you really think
> > that powerd or cron can do this?
> 
> 
> Without question, cron could do it.
> 

I can't see cron using kernel memory; that just doesn't make sense to
me. Not even the periodic scripts that cron executes should be able to
balloon kernel like that. 

I think I know what meant to infer though -- that some nonstandard cron
script is doing something ugly.


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