Instant Recovery for SMIS-A ZDB for HP StorageWorks EVA in HP-UX LVM Mirroring Configuration

HP OpenView Storage Data Protector
Instant Recovery in LVM Mirroring environment 7
Method I – Instant Recovery reducing and extending
In this method, the mirrors are reduced to include only one volume, namely the physical
volume group from which the backup was taken. After the volume is reduced, instant recovery
can be performed cleanly. After the recovery is complete, the logical volume is mirrored again
to include both physical volume groups. The detailed description of the method is as follows:
Caution: Before reducing the mirrors, it should be verified that the mirror which we are
reducing is the correct one. Failing to do so would result in irrecoverable loss of data. The user
is advised to record the mirroring settings, and the output of the commands of lvdisplay and
vgdisplay for the later use.
1. Reduce the mirrors so that only physical volume group, where the instant recovery
would happen is present in the volume group. In the example mentioned it would be
PVG-2.
The command lvreduce is used to reduce the mirrors. For example, if the volume group
VG01 contains a logical volume lvol1, which contains the disks /dev/dsk/c12t0d0
and /dev/dsk/c12t0d1 (belonging to PVG-2) and /dev/dsk/c15t0d0 and
/dev/dsk/c15t0d1 (belonging to PVG-1), then to reduce the volume to contain only
disks from PVG-2, following command can be used:
lvreduce -m 0 /dev/vg01/lvol1 /dev/dsk/c15t0d0
lvreduce -m 0 /dev/vg01/lvol2 /dev/dsk/c15t0d1
You can check this by the command lvdisplay; the sample output is given below:
# lvdisplay –v /dev/vg01/lvol1
--- Logical volumes ---
LV Name /dev/vg01/lvol1
VG Name /dev/vg01
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 1024
Current LE 256
Allocated PE 256
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation PVG-strict
IO Timeout (Seconds) default
--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c12t0d0 255 255
/dev/dsk/c12t0d1 1 1
--- Logical extents ---
LE PV1 PE1 Status 1
00000 /dev/dsk/c12t0d0 00000 current
00001 /dev/dsk/c12t0d0 00001 current
....