[PC-BSD Testing] Panic from ZFS

Bill Leeper protagonist at charter.net
Fri Oct 24 08:53:13 PDT 2008

I was wondering if you would speak up again. Also, for those  
interested here is the link you gave us back in the alpha testing.


I have to admit I am one of those running on a less than optimal  
system, having a 32 bit processor and only 2gb of RAM, but so far I  
have had no problems at all with it. But then this is running on a  
system with no critical data so if things go wrong it is no big deal.

On Oct 24, 2008, at 8:07 AM, Edward O'Callaghan wrote:

> Actually Kris,
> My point was that you could suffer complete data corruption !
> I know about the message as I asked for it to be put there,  
> remember ;)
> I really do think it should be disabled on systems where it should not
> be running on until you are using FreeBSD 8 with the update to version
> 11. That is, that I can now confirm that it does indeed resolve the
> memory issue.
> Regards,
> Edward.
> 2008/10/25 Kris Moore <kris at pcbsd.com>:
>> Arthur wrote:
>>> At 02:49 AM 10/24/2008, you wrote:
>>>> On Fri, Oct 24, 2008 at 7:30 AM, Edward O'Callaghan
>>>> <victoredwardocallaghan at gmail.com> wrote:
>>>>> Hi,
>>>>> You can get version 6 of zfs to panic in FreeBSD by doing the  
>>>>> following;
>>>>> * Have 512 or less MB of RAM
>>>>> * Fill most of your zpool up then run a zpool scrub on the pool..
>>>>> This is a out-of-memory kernel panic that particularly affects  
>>>>> i386.
>>>>> My suggested work around is to put the following into loader.conf
>>>>> vfs.zfs.zil_disable=1
>>>>> vfs.zfs.prefetch_disable=1
>>>>> N.B. Disabling ZIL can have serious consequences depending on
>>>> your workload.
>>>>> FreeBSD 8 upgrades ZFS to version 11. However I am not sure how  
>>>>> this
>>>>> affects things as this only happens on FreeBSD and not Solaris.
>>>>> Kris, As I said before. I highly recommend you disable ZFS  
>>>>> support on
>>>>> 32bit systems with less then 1gb of ram else people _could_ lose  
>>>>> data
>>>>> ?
>>>> I've always believed that there is a HEADS UP somewhere that said
>>>> something about dedicating at least 1GB for ZFS on FreeBSD.
>>> Yes, I remember this as well.
>>> Arthur
>> Correct! If you try to install with ZFS, this message appears  
>> first, and
>> you have to click "OK" to continue:
>> "Warning: ZFS usage is primarily for high-end systems with a 64 bit
>> processor and 4+ GB of memory. It may run on lesser hardware, but  
>> is not
>> recommended."
>> That pretty much covers all the bases here. I don't want to outright
>> disable ZFS, since some users have enjoyed testing / playing with  
>> it on
>> systems with 512MB of ram in qemu / vmware or on a test desktop. Its
>> more of a learning experience for them to just play with zfs and  
>> see how
>> it works. (I've done that myself a bit, on some of my older systems)
>> However, again, the message does let users know that it should have  
>> 4GB
>> of memory, and use the amd64 release if possible.
>> --
>> Kris Moore
>> PC-BSD Software
>> http://www.pcbsd.com
>> _______________________________________________
>> Testing mailing list
>> Testing at lists.pcbsd.org
>> http://lists.pcbsd.org/mailman/listinfo/testing
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> Edward O'Callaghan.
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