Problem with file system on iSCSI FileIO

[Slawomir Nowakowski]

Dear Emmanuel,


> Le Fri, 24 Sep 2010 13:11:25 +0200
> Slawomir Nowakowski<slawomir.nowakowski at open-e.com>  écrivait:
>
>    
>> But we believe the problem is with the XFS. With unknown reason we
>> are not able to mount the LV and after running xfs_repair the file is
>> missing from the LV. Do you have any ideas how we can try to fix the
>> broken XFS?
>>      
> This doesn't really make much sense to me. What target are you using?
> scst, tgt, lio or iet? What looks weird to me is that the dd command
> example you gave writes over the xfs filesystem :
>
> dd if=/dev/zero of=/dev/vg+vg00/lv+i+lv0000 bs=1M conv=notrunc
>
> This is definitely incorrect. Given that /dev/vg+vg00/lv+i+lv0000 is
> your xfs formatted lv, you must mount it somewhere :
>
> mount /dev/vg+vg00/lv+i+lv0000 /mnt/whatever
>
> Then you dd the file on /mnt/whatever :
>
> dd if=/dev/zero of=/mnt/whatever/lunfile bs=1M
>
> Lastly, you declare /mnt/whatever/lunfile as the lun in your target
> (method varies depending upon the target used), something like (ietd
> example):
>
> Target iqn.2010-09:com.whatever.host.target1
> 	Alias host.target1
> 	Lun 0 Type=fileio,Path=mnt/whatever/lunfile,IOMode=wback
>
>    
It's my mistake in dd command, sorry for that.

First we mount the LV:

mount
[...]
/dev/vg+vg00/lv+i+lv0000 on /mnt/point type xfs 
(rw,nouuid,attr2,nobarrier,noquota)
[...]

then we run dd to file

dd if=/dev/zero of=/mnt/point/lun bs=1M conv=notrunc count=$size

$size is counted to leave some free space on the device

As the iSCSI target we use SCST 1.0.1.2. The scst.conf looks likes like 
this:

[HANDLER vdisk]
DEVICE 0QSP199WJI1yKOPj,/mnt/point/lun,WT,512,0QSP199WJI1yKOPj

[GROUP Default_iqn.2010-03:sn1.target0]
[GROUP Default]

[ASSIGNMENT Default_iqn.2010-03:sn1.target0]
DEVICE 0QSP199WJI1yKOPj,0
[ASSIGNMENT Default]

[TARGETS enable]

[TARGETS disable]

The problem is that we were able to use this LUN in the target, but 
suddenly after a reboot we are not.

Cheers
Slawek