Setting "zfs_arc_max" value in FreeBSD 8.

[Artem Belevich]

>> Anyone know if it is adjustable on a system with 1024MB of ram ? Is this
>> just being auto calculated by some other value ?

You may want to make sure that vm.kmem_size is set to a value much
larger than vfs.zfs.arc_max. Default value may be too small to allow
such a large ARC.

On a side note, I'm not sure that ZFS is a good match for system with
only 1G of RAM. By trial and error on my box with 8G or memory I've
figured out that I need to set arc_max ~1G below physical memory size
to avoid lockups under load. YMMV.

--Artem



On Wed, Jan 20, 2010 at 2:14 AM, Alexander Leidinger
<Alexander at leidinger.net> wrote:
> Quoting jhell <jhell at DataIX.net> (from Tue, 19 Jan 2010 09:45:58 -0500):
>
>> On 1/19/2010 5:16 AM, Sherin George wrote:
>>>
>>> Thanks Ivan :)
>>>
>>> I found It. add following in /boot/loader.conf
>>>
>>> ===================
>>> vfs.zfs.arc_max="10244M"
>>> ===================
>
>> I just thought I would give a shout at this for stable/7 as of last
>> week. I am not sure if this is just me but I had tried to adjust
>> zfs_arc_max and found out that it was unadjusted to my value after the
>> system came back up.
>>
>> Anyone know if it is adjustable on a system with 1024MB of ram ? Is this
>> just being auto calculated by some other value ?
>
> Can you confirm that you made the modification in /boot/loader.conf, and
> that you used the double-quotes around the value as shown above?
>
> The code in 7-stable regarding this is the same as in 8-stable and
> 9-current, so if it is done correctly, it has to change accordingly.
>
> Bye,
> Alexander.
>
> --
> You ain't learning nothing when you're talking.
>
> http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
> http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137
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