Date: Mon, 29 Sep 2008 10:13:28 +0200 From: Bartosz Stec <admin@kkip.pl> To: Ben Kelly <bkelly@vadev.org>, freebsd-stable@freebsd.org Subject: Re: vm.kmem_size settings doesn't affect loader? Message-ID: <48E08E28.90009@kkip.pl> In-Reply-To: <C0588997-E405-4651-8D4A-205B8163F97A@vadev.org> References: <48DB6772.1060400@kkip.pl> <20080925130227.GA13497@icarus.home.lan> <48DB9CAA.9060807@kkip.pl> <20080925145154.GA15486@icarus.home.lan> <48DCA0AF.5050000@kkip.pl> <C0588997-E405-4651-8D4A-205B8163F97A@vadev.org>
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Ben Kelly wrote:
> On Sep 26, 2008, at 4:43 AM, Bartosz Stec wrote:
>> Jeremy Chadwick wrote:
>>>
>>> These are the tuning settings I use:
>>>
>>> vm.kmem_size="1536M"
>>> vm.kmem_size_max="1536M"
>>> vfs.zfs.arc_min="16M"
>>> vfs.zfs.arc_max="64M"
>>>
>> Yesterday I've added 512 MB memory to box (sum 1,5GB), and set
>> vm.kmem_size and vm.kmem_size to "1024M". With pieces of 1024MB,
>> 512MB, 256MB, 256MB available and 3 memory slots it is hard to have
>> 2GB RAM ;)
>> Until now it survived world cleaning/building/installing/bonnie++
>> benchmarkink/fs scrubing and general usage. Memory usage seems
>> stable. If unfortunately kmem exhaustion will happen again I will
>> experiment with ARC settings.
>> IMHO you've explained gently a lot of zfs tuning concerns in this
>> thread and they should be added to tuning guide - espacially
>> explanation of ARC and prefetch settings. Thanks again!
>
> Did you increase KVA_PAGES in your kernel config as well?
>
> The default of 256 only allows 1GB of kernel memory total. Setting
> KVA_PAGES to 384 would probably be good for a kmem_size of 1GB. This
> would give leave you with 512MB of space for other things in the
> kernel. In your kernel config:
>
> options KVA_PAGES=384
>
> Sorry if you already knew this. I know its in the zfs tuning guide.
> I just hadn't seen it mentioned in the thread yet and wanted to make
> sure it wasn't missed.
>
> Hope that helps.
>
> - Ben
>
Indeed I know that.
options KVA_PAGES=512
is included in my kernel config.
Until now:
# uptime
10:12 up 3 days, 10:32, 1 user, load averages: 0,00 0,03 0,00
Thanks :)
--
Bartosz Stec
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