Date: Tue, 27 Nov 2012 12:27:24 -0800 From: Rumen Telbizov <telbizov@gmail.com> To: "freebsd-stable@freebsd.org" <freebsd-stable@freebsd.org> Subject: Re: ZFS memory management Message-ID: <CAENR%2B_VnTm6cVM0koeA4i8aeU92nii4Yxx-M2POaCNTk_pGweA@mail.gmail.com> In-Reply-To: <CAOjFWZ4MsOmOEXuO8pzMKqN3_ykA7i=jkcMYxPT-6xdWVerfsw@mail.gmail.com> References: <7A88B836-C985-446C-A992-A295A2474A38@gmail.com> <CAOjFWZ4MsOmOEXuO8pzMKqN3_ykA7i=jkcMYxPT-6xdWVerfsw@mail.gmail.com>
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> > - 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 And this is what Nikolay did after the incident apparently. The question was more like: Shouldn't the OS release this memory automatically when it's starved as opposed to nuking processes? It's only cache after all. Lots of it. On Tue, Nov 27, 2012 at 12:22 PM, Freddie Cash <fjwcash@gmail.com> wrote: > 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 > > :) > > > 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" > -- Rumen Telbizov http://telbizov.com
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