can't create snapshot on FC2

Hi list,

I'm trying to create snapshot on lvm2 rinning on a fresh Fedora Core 2 linux machine kernel 2.6.5-1 lvm versions (pvdisplay --version output)
LVM version: 2.00.15 (2004-04-19)
Library version: 1.00.14-ioctl (2004-04-06)
Driver version: 4.1.0

I did the followings:
-- snip --
pvcreate /dev/sdb
vgcreate extdisk /dev/sdb
lvcreate -L500g -npart1 extdisk
mke2fs -j /dev/extdisk/part1
-- snap --
till here everything was fine - I could mount the partition and use it w/o any problem... then I unmounted the partition and tried to create a snapshot using this syntax :
lvcreate -L50g -s -n userssnap /dev/extdisk/part1
then I got this:
device-mapper ioctl cmd 9 failed: Invalid argument
Couldn't load device 'extdisk-userssnap'.
Problem reactivating origin part1

and then I could not mount the partiton again (the mount command just hang..)

here is my lvdisplay output:
-- snip --
--- Logical volume ---

 LV Name                /dev/extdisk/part1
 VG Name                extdisk
 LV UUID                NNuptN-60Hx-B403-c1uc-FVp6-Kr03-AqJ8CE
 LV Write Access        read/write
 LV snapshot status     source of
                        /dev/extdisk/userssnap [INACTIVE]
 LV Status              suspended
 # open                 0
 LV Size                500.00 GB
 Current LE             128000
 Segments               1
 Allocation             next free (default)
 Read ahead sectors     0
 Block device           253:1

--- Logical volume ---

 LV Name                /dev/extdisk/userssnap
 VG Name                extdisk
 LV UUID                gU4N1Y-0CWf-F6Oo-fRuZ-EpAX-fRFg-pgtAn4
 LV Write Access        read/write
 LV snapshot status     INACTIVE destination for /dev/extdisk/part1
 LV Status              available
 # open                 0
 LV Size                500.00 GB
 Current LE             128000
 Segments               1
 Snapshot chunk size    8.00 KB
 Allocated to snapshot  100.00%
 Allocation             next free (default)
 Read ahead sectors     0
 Block device           253:4

-- snap --

any idea how to debug it / how to create a snapshot ??

thanks

--Yedidia Klein
Jerusalem College of Technology
Computing Center

Fedora doesn't include kernel support for snapshots/mirrors yet.

To use them you'd need to patch your kernel.
http://sources.redhat.com/dm/

Alasdair

[email protected]

tnx,
Is anyone using lvm2 snapshot in productions ?
I would like to use it w/ a storage system - is it ready for production ??

--Yedidia Klein