1
Introduction
1) What is the need for this conversion?
Whenever the total
number of PVs in a Normal VG reaches max PV limit (32 PVs/VG), we can not add
new PVs in the VG. But if we convert the Normal VG to Big VG Format, we can
accommodate 128 PVs in a single VG.
2
How to Convert the VG Format?
What are the pre-requisites?
While converting a Normal VG to
Big VG format, the VGDA gets expanded.
So we need at least 1 free PP per PV in all the PV residing in the VG.
If not we have to follow the following method to move date from the used PPs
from a PV to an unused PP in another PV.
How to move PPs across PVs?
Use the below command to view the current PVs in the VG and Total/Free
PPs per PV.
$ lsvg -p vg000
vg000:
PV_NAME PV STATE TOTAL PPs
FREE PPs FREE DISTRIBUTION
vpath1 active
595
594
118..119..119..119..119
vpath2 active 595
247
09..00..00..119..119
vpath0 active
595 0
00..00..00..00..00
vpath3 active
595 0
00..00..00..00..00
Here vpath0 and vpath3 don’t have any free PPs. In this case, we should
move 1 used PP from both the PV to some unused PP in vpath1 or vpath2.
Before moving, please collect the below information.
VGID : You can get this info from lsvg
command.
Source PVID : You can get this info from lspv <pv_name>
Source PP No. : This PP should be an used PP from the
source PV.
You
can get this info from lspv –M <pv_name>
Target PVID : You can get this info from lspv
<pv_name>
Target PP No. : This PP should be an unused PP from
the Target PV.
You can get this
info from lspv –M <pv_name>
After the collection of the above details, use the below command to
migrate the data from unused PP to used PP.
lmigratepp -g VGid -p SourcePVid -n SourcePPnumber
-P DestinationPVid -N DestinationPPnumber
After achieving the pre-requisites, check the OS version.
For AIX Version 5.1, use Method 1 to convert the VG to Big format.
For AIX Version 5.2 and above, use Method 2 to convert the VG to Big
format.
Method 1:
- Arrange
for the outage for this VG.
- During
outage execute the below mentioned commands:
- umount
all the file systems belonging to the VG.
- Run
`chvg –B <vg_name>`.
This command takes bit long time since it
expands the VGDA for all the PVs belonging to this VG.
Method 2:
1. Run `chvg –B <vg_name>`.
This command takes bit long time since it
expands the VGDA for all the PVs belonging to this VG.
3
Check the result
Run `lsvg <vg_name>` and verify the Max PVs Field. It should be
128 for a Big VG.
$ lsvg vg000
VOLUME GROUP: vg000 VG IDENTIFIER: 00597f2a068e49c0
VG STATE: active PP SIZE: 8 megabyte(s)
VG PERMISSION: read/write TOTAL PPs: 2380 (19040 megabytes)
MAX LVs: 256 FREE PPs: 841 (6728 megabytes)
LVs: 2 USED PPs: 1539 (12312 megabytes)
OPEN LVs: 2 QUORUM: 3
TOTAL PVs: 128 VG DESCRIPTORS: 128
STALE PVs:
0 STALE PPs: 0
ACTIVE PVs: 128
AUTO ON: yes
MAX PPs per PV: 1016 MAX PVs: 128
