ZFS deadlock

[Johan Ström]

On Apr 8, 2008, at 9:32 AM, Jeremy Chadwick wrote:

> On Tue, Apr 08, 2008 at 08:17:38AM +0200, Johan Ström wrote:
>> Hello
>>
>> A box of mine running RELENG_7_0 and ZFS over a couple of disks (6  
>> disks, 3
>> mirrors) seems to have gotten stuck. From Ctrl-T:
>>
>> load: 0.50  cmd: zsh 40188  
>> [zfs:&buf_hash_table.ht_locks[i].ht_lock] 0.02u
>> 0.04s 0% 3404k
>> load: 0.43  cmd: zsh 40188  
>> [zfs:&buf_hash_table.ht_locks[i].ht_lock] 0.02u
>> 0.04s 0% 3404k
>> load: 0.10  cmd: zsh 40188  
>> [zfs:&buf_hash_table.ht_locks[i].ht_lock] 0.02u
>> 0.04s 0% 3404k
>> load: 0.10  cmd: zsh 40188  
>> [zfs:&buf_hash_table.ht_locks[i].ht_lock] 0.02u
>> 0.04s 0% 3404k
>> load: 0.11  cmd: zsh 40188  
>> [zfs:&buf_hash_table.ht_locks[i].ht_lock] 0.02u
>> 0.04s 0% 3404k
>>
>> Worked for a while then that stopped working too (was over ssh). When
>> trying a local login i only got
>>
>> load: 0.09  cmd: login 1611 [zfs] 0.00u 0.00s 0% 208k
>>
>> I found one post like this earlier (by Xin LI), but nobody seemed  
>> to have
>> replied...
>> in my current conf, I think my kmem/kmem_max is at 512Mb (not sure  
>> though,
>> since I've edited my file yesterday for next reboot), with 2G of  
>> system
>> RAM.. Normally I'd run kmem(max) 1G (with arcsize of 512M.  
>> currently it is
>> at default), but since I just got back to 2G total mem after some  
>> hardware
>> problems I've been runnig at those lows (1G total is kindof tight  
>> with
>> zfs..)
>>
>> Well, just wanted to report... The box is not totally dead yet, ie  
>> I can
>> still do Ctrl-T on console, but thats it.. I don't really know what  
>> more I
>> can do so.. I don't have KDB/DDB.
>> I'll wait another hour or so before I hard reboot it, unless it  
>> "unlocks"
>> or if anyone have any suggestions.
>
> I don't think there are any suggestions left to give.  Many people,
> including myself, have experienced this kind of problem.  It's well-
> documented both on my Common Issues page, and the official FreeBSD ZFS
> Wiki.

Ah.. I guess I was just to restrictive with the googling on  
"zfs:&buf_hash_table.ht_locks[i].ht_lock".
>
>
> ZFS is still considered highly experimental, so if your data is at all
> important to you, perform backups or switch to another filesystem
> provider.

That I am aware of.

Thanks.