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From: Ben Kelly <ben@wanderview.com>
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Date: Wed, 5 May 2010 10:12:49 -0400
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To: Pawel Jakub Dawidek <pjd@freebsd.org>
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Cc: freebsd-fs@freebsd.org, FreeBSD Stable <freebsd-stable@freebsd.org>
Subject: Re: Freebsd 8.0 kmem map too small
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On May 5, 2010, at 9:33 AM, Pawel Jakub Dawidek wrote:

> On Wed, May 05, 2010 at 10:46:31AM +0200, Giulio Ferro wrote:
>> On 05.05.2010 09:52, Jeremy Chadwick wrote:
>>=20
>> Nope, it's happened again... Now I've tried to rise vm.kmem_size to =
6G...
>>=20
>>=20
>>> Did you set both vm.kmem_size and vfs.zfs.arc_max, setting the =
latter to
>>> something *less* than vm.kmem_size?
>>>=20
>>>=20
>>=20
>> Yes.
>> After your suggestion, I set
>> vfs.zfs.arc_max: 3758096384
>> vm.kmem_size: 4G
>>=20
>> Now:
>> vfs.zfs.arc_max: 3758096384
>> vm.kmem_size: 6392119296
>=20
> Could you try to track down the commit that is causing your problems?
> Could you try 8-STABLE kernel from before r206815?


Are others generally able to run ARC values so close to kmem size?  My =
experience has been that you really need the ARC to be much smaller than =
the kmem limit (like 25% or less) due to fragmentation of kmem_map.

- Ben=