Re: ZFS Hangs

Thomas Sparrevohn wrote:
> On Sunday 04 November 2007 12:02:08 Peter Schuller wrote:
>>> It certainly could be a caching effect but the particular problem you
>>> were seeing should have been fixed.  Are you still seeing it?
>> I am not still seeing it; the machine has since been switched to AMD 64, and 
>> RAM increased from 1 GB to 3 GB (and FreeBSD itself upgraded several times 
>> since then). I did not look into it in terrible detail; I just observed by 
>> tracing that the I/O in question was definitely the package database, and 
>> that it was definitely accessing the same files mutiple times. I assumed it 
>> was a caching effect at the time, given all the maxvnode tweaking and sizing 
>> restrictions put on the ARC. I do know I never saw it after the memory 
>> increase.
>>
>> Also, this might have been prior to disabling prefetch. If it was, perhaps the 
>> prefetch hosed the cache. (Are the prefetch issues still there, anyone?)
>>
> 
> Hmm. I seeing the hang now - but had not been seeing it before as I had increased the arc cache
> size - seems a very low arc_max - its about 300MB on a 4GB amd64 system 
> 
> However  ZFS haning in "zfs:(&zio_cv_io)" is new - I have been running this system using ZFS for month
> without any trouble - The only change I can think of is that the devices has been changes to ATA RAID 0+1 
> apart from that everything worked before the 28/10-2007 - that when I installed the extra disks to change
> from RAID 0 - to RAID 0+1 -   
> 
> 

http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/kerneldebug.html

Kris