Hi Sanjeev,

Thank you! I was not able to find anything as useful on the subject as
that!  We are running build 54 on an X4500, would I be correct in my
reading of that article that if I put "set zfs:zfs_arc_max =
0x100000000 #4GB" in my /etc/system, ZFS will consume no more than
4GB? Thank you in advance.

Best Regards,
Jason

On 1/8/07, Sanjeev Bagewadi <[EMAIL PROTECTED]> wrote:
Jason,

Jason J. W. Williams wrote:

> Thank you very much! I'm not very familiar with using mdb. Is there
> anything to be aware of besides no active zpools?

you can do the following as root user :
-- snip --
# mdb -kw
 > arc::print -a "struct arc" c_max
ffffffffc009a538 c_max = 0x2f9aa800
 > ffffffffc009a538/W 0x20000000
arc+0x48:       0x2f9aa800      =       0x20000000
 >
-- snip --
Here I have modified the value of c_max from 0x2f9aa800 to 0x20000000.

>
> Also, which takes precedence 3/4 of the memory or 1GB? Thank you in
> advance! Your help is greatly appreciated.

Whichever is higher. Look at the routine arc_init() [Line  2544] at :
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/zfs/arc.c

And I think your request has been answered :-)
Looking at the source I see that they have introduced two new variables
 zfs_arc_max and zfs_arc_min which seem to be tunables !

There is a detailed explaination at :
http://bugs.opensolaris.org/bugdatabase/view_bug.do?bug_id=6505658

Thanks and regards,
Sanjeev.

>
> Best Regards,
> Jason
>
> On 1/7/07, Sanjeev Bagewadi <[EMAIL PROTECTED]> wrote:
>
>> Jason,
>>
>> There is no documented way of limiting the memory consumption.
>> The ARC section of ZFS tries to adapt to the memory pressure of the
>> system.
>> However, in your case probably it is not quick enough I guess.
>>
>> One way of limiting the memory consumption would be limit the arc.c_max
>> This (arc.c_max) is set to 3/4 of the memory available (or 1GB less than
>> memory available).
>> This is done when the ZFS is loaded (arc_init()).
>>
>> You should be able to change the value of arc.c_max through mdb and set
>> it to the value
>> you want. Exercise caution while setting it. Make sure you don't have
>> active zpools during this operation.
>>
>> Thanks and regards,
>> Sanjeev.
>>
>> Jason J. W. Williams wrote:
>>
>> > Hello,
>> >
>> > Is there a way to set a max memory utilization for ZFS? We're trying
>> > to debug an issue where the ZFS is sucking all the RAM out of the box,
>> > and its crashing MySQL as a result we think. Will ZFS reduce its cache
>> > size if it feels memory pressure? Any help is greatly appreciated.
>> >
>> > Best Regards,
>> > Jason
>> > _______________________________________________
>> > zfs-discuss mailing list
>> > zfs-discuss@opensolaris.org
>> > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>>
>>
>>
>> --
>> Solaris Revenue Products Engineering,
>> India Engineering Center,
>> Sun Microsystems India Pvt Ltd.
>> Tel:    x27521 +91 80 669 27521
>>
>>
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss@opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss



--
Solaris Revenue Products Engineering,
India Engineering Center,
Sun Microsystems India Pvt Ltd.
Tel:    x27521 +91 80 669 27521


_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss

Reply via email to