Repeatable ZFS "kmem map too small" panic on 8.0-STABLE

[Doug Poland]

On Fri, January 22, 2010 00:09, Artem Belevich wrote:
> On Thu, Jan 21, 2010 at 8:28 PM, Doug Poland <doug at polands.org>
> wrote:
>> Interesting discussion :)  I added vm.kmem_size="20G" to
>> /boot/loader.conf per your instructions.  This time, it didn't
>> panic at the same point in the test, however, it appears the
>> filesystem is "hanging".
>>
>> On the fdisk test, I hit <CTRL> T and get:
>> cmd: fsdisk 37066 [zio->io_cv)] 245.62r 0.12u 25.10s 0
>>
>> My various metrics are still running, but anything that needs the
>> filesystem appears "stuck".
>>
>> The memory usage of the item "solaris" (vmstat -m | grep solaris)
>> spiked at 3334781952 (3180.30 MiB).
>>
>> # zpool iostat 2, a <CTRL> T shows:
>> load: 0.00  cmd: zpool 934 [tx->tx_quiesce_done_cv)] 2052.45r 0.06
u 0.39s 0% 0k
>>
>> # vmstat -v | grep solaris to disk every second and it's hung at:
>> load: 0.00  cmd: sh 38551 [zfs] 909.85r 0.00u 0.00s 0% 16k
>>
>> Any suggestions!
>>
> Next step would be to set vfs.zfs.arc_max to a value that's somewhat
> below your physical memory size. Let's say - 1G or so. On my box with
> 8GB of RAM I set these values:
>
> vfs.zfs.arc_max="6500M"
> vfs.zfs.arc_min="4G"
>
OK, I'll give that a shot...

> You didn't mention how recent is your kernel. There were quite a few
> bugfixes committed to -8. Make sure your kernel is r201987 or newer.
>
Right now I'm running a stock 8.0-RELEASE.  I had tried it on -STABLE
a couple of days ago with similar results.  I'll get the box back up
to -STABLE again.  Do you advise to upgrade the pool to v14 for this
testing?


-- 
Regards,
Doug