XEN disk file corrupt

[Maaz]

XEN disk file corrupt

dom0 OS: SLES 10 SP2
domU OS(paravirtual guest): SLES 10 SP2
SAN: HP HSV 200, FC connected

Problem
domU(SLES10 SP2) doesn't boots/start, after reducing the size of FC connected SAN disk, /dev/mapper/3600508b40006e2cc0000c000005d0000 (before it was 350 GB, then after reduction it is 250 GB)

in dom0,
/dev/mapper/3600508b40006e2cc0000c000005d0000 mounted on /var/lib/xen/images

# cd /var/lib/xen/images/sles10-1so
# fdisk -l disk0

# du -h fdisk
6.5G disk0

then I ran fsck in dom0
# reiserfsck --rebuild-tree dev/mapper/3600508b40006e2cc0000c000005d0000

Pass 0:
####### Pass 0 #######
Loading on-disk bitmap .. ok, 34700582 blocks marked used
Skipping 10450 blocks (super block, journal, bitmaps) 34690132 blocks will be read
0%block 203170: The number of items (15) is incorrect, should be (1) - corrected
block 203170: The free space (0) is incorrect, should be (3792) - corrected
pass0: vpf-10200: block 203170, item 0: The item [4096 16778752 0x100010003070000 IND (1)] with wrong offset is deleted
....20%....block 25657137: The number of items (59392) is incorrect, should be (1) - corrected
block 25657137: The free space (45944) is incorrect, should be (3792) - corrected
pass0: vpf-10110: block 25657137, item (0): Unknown item type found [4294858473 3733539071 0xe8e7894c ??? (15)] - deleted

40%....60%....80%....100% left 0, 24326 /sec
12651 directory entries were hashed with "r5" hash.
"r5" hash is selected
Flushing..finished
Read blocks (but not data blocks) 34690132
Leaves among those 36693
- corrected leaves 1537
- leaves all contents of which could not be saved and del
pointers in indirect items to wrong area 1554648 (zeroed)
Objectids found 12654

Pass 1 (will try to insert 36687 leaves):
####### Pass 1 #######
Looking for allocable blocks .. finished
0%....20%....40%....60%....80%....100% left 0, 203 /sec
Flushing..finished
36687 leaves read
36677 inserted
10 not inserted
####### Pass 2 #######

Pass 2:
0%....20%....40%....60%....80%....100% left 0, 20 /sec
Flushing..finished
Leaves inserted item by item 10
Pass 3 (semantic):
####### Pass 3 #########
/sles10-1so/res/disk0vpf-10680: The file [29 34] has the wrong block count in the StatData (12582912) - corrected to (0)
Flushing..finished
Files found: 12193
Directories found: 460
Broken (of files/symlinks/others): 1
Pass 3a (looking for lost dir/files):
####### Pass 3a (lost+found pass) #########
Looking for lost directories:
Flushing..finishede 1, 0 /sec
Pass 4 - finished done 0, 0 /sec
Deleted unreachable items 1536
Flushing..finished
Syncing..finished
###########
reiserfsck finished at Thu Jan 15 12:53:58 2009

but still domU doesnt start
# xm start -c sles10-1so
Using config file "./sles10-1so".
Error: Boot loader didn't return any data!

# cd /var/lib/xen/images
# reiserfsck --check disk0
bread: End of file, cannot read the block (1572863).


QUESTIONS:
--------
is there any possibility to recover/mend the disk file (disk0) ?


when I ran fsck in dom0
# reiserfsck --rebuild-tree dev/mapper/3600508b40006e2cc0000c000005d0000

fsck reports that it has recovered the filesystem then why xen disk is still not recovered ?

and please confirm, If i reduce the disk size of a san disk ? file system will become corrupt ?

Thanks and Regards

[Heironimus]

Did you reduce the filesystem before you reduced the SAN volume? If you made the SAN volume smaller than the filesystem then you did corrupt it and probably can not fix it because some of the data you need was probably on the space that you took away.