[linux-lvm] lvreduce nightmare

[tariq wali]

Hi,

 I tried to reduce the VG and this is what it looked like before I tried to
reduce it

Filesystem                       Size  Used Avail   Use% Mounted on
/dev/mapper/vg0-data         2.2T  1.7T  433G  80%  /data

Out of the available *433G* I wanted to reduce *100G* in vg0 so that I
could use it for a new partition and this is what I did ..

* e2fsck -f /dev/vg0/data
resize2fs /dev/vg0/data 100G
lvreduce -L -100G -n /dev/vg0/data*

lvs
  LV   VG   Attr   LSize Origin Snap%  Move Log Copy%  Convert
  data vg0  -wi-ao 2.08T

after the lvreduce it did what I intended to as you can see in

vgs
  VG   #PV #LV #SN Attr   VSize VFree
  vg0    1   1   0 wz--n- 2.18T *100.00G*   ( it did allocate the 100.00G
as free space )

after I mounted /data back , I could even touch a file , however when we
start the app (mysql) and when it tries to write into the existing data in
/data , the drive goes into *read only mode repeatedly* ..

in order to fix it i unmounted /data and ran

*e2fsck -f /dev/vg0/data -n*
*
*
after the fsck completed it would prompt to fix superblock/inodes which I
replied with 'yes' however the problem still persists that if i mount /data
it goes into read-only mode .

dmsetup table
vg0-data: 0 4477255680 linear 104:17 384

Red Hat Enterprise Linux Server release 5.7
2.6.18-274.17.1.el5 #1 SMP  x86_64
lvm2-2.02.84-6.el5_7.1

I have reduced lvm's with those  sequence of commands in the past but i
just dont understand why it seems to have failed this time although i did
get 100G free space in vg0 but the partition /data seems useless ..

* I would greatly appreciate any help/insights .. i notice lvm has created
a backup file in /etc/lvm/archive as   vg0_00008-1147866134.vg , does
restoring from that file actually work ? will it get the drive into
original state ? and how can i actually free some space from the volume
group if i want to ?*


########
some errors spewed in dmesg

attempt to access beyond end of device
dm-0: rw=0, want=4654102632, limit=4477255680
EXT3-fs error (device dm-0): read_block_bitmap: Cannot read block bitmap -
block_group = 17145, block_bitmap = 561807360
Aborting journal on device dm-0.
attempt to access beyond end of device
dm-0: rw=0, want=4565762056, limit=4477255680
EXT3-fs error (device dm-0): read_block_bitmap: <2>ext3_abort called.
EXT3-fs error (device dm-0): ext3_journal_start_sb: Detected aborted journal

Cannot read block bitmap - block_group = 17417, block_bitmap = 570720256
EXT3-fs error (device dm-0): read_block_bitmap: Cannot read block bitmap -
block_group = 17417, block_bitmap = 570720256
dm-0: rw=0, want=4683202568, limit=4477255680
EXT3-fs error (device dm-0): read_block_bitmap: Cannot read block bitmap -
block_group = 17865, block_bitmap = 585400320

EXT3-fs error (device dm-0) in ext3_free_blocks_sb: Journal has aborted
EXT3-fs error (device dm-0) in ext3_orphan_del: Journal has aborted
__journal_remove_journal_head: freeing b_committed_data


ext3_abort called.
EXT3-fs error (device dm-0): ext3_put_super: Couldn't clean up the journal
kjournald starting.  Commit interval 5 seconds
EXT3-fs warning (device dm-0): ext3_clear_journal_err: Filesystem error
recorded from previous mount: IO failure
EXT3-fs warning (device dm-0): ext3_clear_journal_err: Marking fs in need
of filesystem check.
EXT3-fs warning: mounting fs with errors, running e2fsck is recommended
attempt to access beyond end of device
dm-0: rw=0, want=4654102632, limit=4477255680

EXT3-fs error (device dm-0): read_block_bitmap: Cannot read block bitmap -
block_group = 17145, block_bitmap = 561807360
Aborting journal on device dm-0.






-- 
*Tariq Wali.*
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