Hello everyone,
I have the following problem: I want to use a snapshot mechanism external to
LVM2 (i.e. snapshot from the storage server) so it happens that I access from a
linux box two identical LUNs with the same PVID. It is not a matter of
multipathing, they just are completely different devices with the same content
(and with the same PVID of course).
What I would like to do is to use and mount the second device on a different
mount point. So:
/dev/sdd1 is the primary PV
/dev/sdf1 is the snapshot of the primary PV
The result of pvscan before the discovery is:
drdb2:~ # pvscan
PV /dev/sde1 VG drrg2_vg lvm2 [200.00 GB / 0 free]
PV /dev/sdd1 VG test_vg lvm2 [200.00 GB / 0 free]
PV /dev/sdb1 VG oracledb_vg lvm2 [220.00 GB / 0 free]
PV /dev/sdc1 VG oracledb_vg lvm2 [20.00 GB / 0 free]
PV /dev/sda3 VG root_vg lvm2 [59.75 GB / 47.26 GB free]
Total: 5 [699.73 GB] / in use: 5 [699.73 GB] / in no VG: 0 [0 ]
after the discovery of the new device is:
drdb2:~ # pvscan
Found duplicate PV PnvnzL7YFft76Ky0EaPbOh519SQD5Uxc: using /dev/sdf1 not
/dev/sdd1
PV /dev/sde1 VG drrg2_vg lvm2 [200.00 GB / 0 free]
PV /dev/sdd1 VG test_vg lvm2 [200.00 GB / 0 free]
PV /dev/sdb1 VG oracledb_vg lvm2 [220.00 GB / 0 free]
PV /dev/sdc1 VG oracledb_vg lvm2 [20.00 GB / 0 free]
PV /dev/sda3 VG root_vg lvm2 [59.75 GB / 47.26 GB free]
Total: 5 [699.73 GB] / in use: 5 [699.73 GB] / in no VG: 0 [0 ]
I guess this problem is the same I'd have if I copy any single byte from a
device to another the last one resulting in having the same LVM label.
What I tried is to:
1) vgreduce:
drdb2:~ # vgreduce test_vg /dev/sdf1
Found duplicate PV PnvnzL7YFft76Ky0EaPbOh519SQD5Uxc: using /dev/sdf1 not
/dev/sdd1
Physical Volume "/dev/sdf1" not found in Volume Group "test_vg"
sdf1 does not belong to test_vg
2) pvchange --uuid:
drdb2:~ # pvchange --uuid /dev/sdf1
Found duplicate PV PnvnzL7YFft76Ky0EaPbOh519SQD5Uxc: using /dev/sdd1 not
/dev/sdf1
Volume group containing /dev/sdf1 has active logical volumes
0 physical volumes changed / 1 physical volume not changed
My idea was to modify the PVID so to let LVM understand they are completely
different devices.
How can I manage this?
Thanks for any help you may give me.
Tommaso
--
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| Tommaso Cecchi CINECA
| System Management Group Via Magnanelli 6/3 40033
| e-mail: t.cecchi@cineca.it Casalecchio di Reno
| Tel: 051/6171411 Bologna - ITALY
| Fax 051/6132198 http://www.cineca.it
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