Re: Xfs Access to block zero exception and system crash

[Sagar Borikar <sagar_borikar@pmc-sierra.com>]

Dave Chinner wrote:
> On Mon, Jun 30, 2008 at 03:54:44PM +0530, Sagar Borikar wrote:
>   
>> After running my test for 20 min, when I check the fragmentation status  
>> of file system, I observe that it
>> is severely fragmented.
>>     
>
> Depends on your definition of fragmentation....
>
>   
>> [root@NAS001ee5ab9c85 ~]# xfs_db -c frag -r /dev/RAIDA/vol
>> actual 94343, ideal 107, fragmentation factor 99.89%
>>     
>
> And that one is a bad one ;)
>
> Still, there are a lot of extents - ~1000 to a file - which
> will be stressing the btree extent format code.
>
>   
>> Do you think, this can cause the issue?
>>     
>
> Sure - just like any other workload that generates enough
> extents. Like I said originally, we've fixed so many problems
> in this code since 2.6.18 I'd suggest that your only sane
> hope for us to help you track done the problem is to upgrade
> to a current kernel and go from there....
>
> Cheers,,
>
> Dave.
>   
Thanks again Dave. But we can't upgrade the kernel as it is already in 
production and on field.
So do you think, periodic cleaning of file system using xfs_fsr can 
solve the issue? If not, could you
kindly direct me what all patches were fixing similar problem? I can try 
back porting them.

Thanks
Sagar