ZFS crashes on heavy threaded environment

Chao Shin quakelee at geekcn.org
Tue Nov 18 01:20:52 PST 2008


On Mon, 17 Nov 2008 23:58:35 +0800,Pawel Jakub Dawidek <pjd at freebsd.org>  
wrote:

> On Thu, Nov 13, 2008 at 06:53:41PM -0800, Xin LI wrote:
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> Xin LI wrote:
>> > Hi, Pawel,
>> >
>> > We can still reproduce the ZFS crash (threading+heavy I/O load) on a
>> > fresh 7.1-STABLE build, in a few minutes:
>> >
>> > /usr/local/bin/iozone -M -e -+u -T -t 128 -S 4096 -L 64 -r 4k -s 30g  
>> -i
>> > 0 -i 1 -i 2 -i 8 -+p 70 -C
>> >
>> > I have included a backtrace output from my colleague who has his hands
>> > on the test environment.  Should there is more information necessary
>> > please let us know and we wish to provide help on this.
>>
>> Further datapoint.  The system used to run with untuned loader.conf, and
>> my colleague just reported that with the following loader.conf, the
>> problem can be triggered sooner:
>>
>> vm.kmem_size_max=838860800
>> vm.kmem_size_scale="2"
>>
>> The system is running FreeBSD/amd64 7.1-PRERELEASE equipped with 8GB of
>> RAM with GENERIC kernel.
>
> With new ZFS I get:
>
> Memory allocation failed:: Cannot allocate memory
>
> Is this expected?
>

At first, Congratulations to you, thanks to your works, well done!

I used this command on a FreeBSD 7.1-PRERELEASE amd64 box with 8GB mem,  
isn't got output like that, but kernel panic.
Maybe you should lower the threads and file size, for example:

/usr/local/bin/iozone -M -e -+u -T -t 64 -S 4096 -L 64 -r 4k -s 2g -i 0 -i  
1 -i 2 -i 8 -+p 70 -C

Actually, we had used this command to test a 8-current with zfs v12 patch  
on July, there is no more panic. So we hope
zfs v13 can MFC as soon as possible, because we really need it now.
-- 
The Power to Serve


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