Date: Thu, 29 Nov 2012 19:16:54 +0200 From: Nikolay Denev <ndenev@gmail.com> To: Olivier Smedts <olivier@gid0.org> Cc: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org> Subject: Re: ZFS memory management Message-ID: <D0B12906-2E5A-4CD5-B7E3-78EB7CD04A4C@gmail.com> In-Reply-To: <CABzXLYOuVGX1wPuHMq8LAn=d%2BeVsjRDtfLt-2X-D_=ChAztG-w@mail.gmail.com> References: <7A88B836-C985-446C-A992-A295A2474A38@gmail.com> <CAOjFWZ4MsOmOEXuO8pzMKqN3_ykA7i=jkcMYxPT-6xdWVerfsw@mail.gmail.com> <CABzXLYOuVGX1wPuHMq8LAn=d%2BeVsjRDtfLt-2X-D_=ChAztG-w@mail.gmail.com>
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On Nov 29, 2012, at 4:53 PM, Olivier Smedts <olivier@gid0.org> wrote: > 2012/11/27 Freddie Cash <fjwcash@gmail.com>: >> Read any ZFS tuning manual on the web, including the ones direct from >> SUN/Oracle, and they all list: >> - if you are running processes that need a lot of memory, then limit the >> ARC to allow the apps to have access to that memory > > Or you could have at least a little swap (good practice) to allow ARC > take the time to evict some memory when under pressure. > Yes, this was already suggested off-list, and it seems like a solution. Thanks to all for the input! >> >> :) >> >> >> On Tue, Nov 27, 2012 at 12:10 PM, Nikolay Denev <ndenev@gmail.com> wrote: >> >>> Hello list, >>> >>> I have the following question : I have several machines with 196G of RAM >>> that are using >>> RELENG_9 with ZFS, and are running a very memory intensive java >>> applications - ElasticSearch >>> The machines are without swap configured and have "vm.swap_enabled=0" in >>> /etc/sysctl.conf. >>> The ElasticSearch processes are using mlockall(2) to pin down their memory >>> (configured at 40G). >>> And at this point I thought that there would be no problems, but from time >>> to time, when the machine grows it's >>> ARC memory and there are some other running processes like nginx with >>> passenger and uwsgi the ElasticSearch >>> process would get killed by the kernel OOM killer with reason "no swap >>> space available" >>> >>> Of course, I've now tuned down arc_max in /boot/loader.conf, but isn't >>> this supposed to work automatically? Like >>> ZFS releasing some memory when there is a pressure, instead of the OOM >>> killer going postal? (at the moment when >>> the process was killed the ZFS ARC was 132G). >>> >>> I understand that this might be problematic as AFAIK ZFS releases memory >>> asynchronously when the arc_reclaim_thread() is run, >>> which might take some time to be scheduled and complete. >>> >>> Cheers, >>> Nikolay >>> >>> >>> _______________________________________________ >>> freebsd-stable@freebsd.org mailing list >>> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >>> To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >>> >> >> >> >> -- >> Freddie Cash >> fjwcash@gmail.com >> _______________________________________________ >> freebsd-stable@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >> To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > > > > -- > Olivier Smedts _ > ASCII ribbon campaign ( ) > e-mail: olivier@gid0.org - against HTML email & vCards X > www: http://www.gid0.org - against proprietary attachments / \ > > "Il y a seulement 10 sortes de gens dans le monde : > ceux qui comprennent le binaire, > et ceux qui ne le comprennent pas."help
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