System locking up.

[Graeme Dargie]

Hi All,

I have a system that is being problematic, I suspect but I cannot say for sure it is maybe related to ZFS as I have a fairly large ZFS pool on the machine. The system will just lock up, local console does not respond to the keyboard, num lock still changes the led on the keyboard, the system still responds to pings but you cannot ssh to the unit. The behaviour is random the system can be running for 50 days plus with no issues then suddenly it enters this state, the error logs do not show anything.

System 8.2-RELEASE FreeBSD 8.2-RELEASE #0
AMD 64

Running on an AMD x2 5600
4gb of DDR2
Gmirror 80gb boot disks
6 x 1.5TB SATA II disks using AHCI


Loader.conf

vfs.zfs.prefetch_disable=0
//vfs.zfs.txg.timeout="5"
vm.kmem_size="1024M"
vm.kmem_size_max="1024M"
vfs.zfs.arc_max="100M"
vfs.zfs.vdev.cache.size="100M"

ZFS filesystem version 4
ZFS storage pool version 15

Is this likely to be a case of just not enough ram? Or is there some other trouble shooting I could do to try and nail down what is going on as it tends to happen when the ZFS zpool is being accessed heavily.

Regards

Graeme