Re: append-only file
From: Lamar Saxon (Lamar.Saxon_at_AMERICREDIT.COM)
Date: Fri, 10 Dec 2004 14:36:55 -0600 To: aix-l@Princeton.EDU
Have you looked in to converting to a BIG VG with the chvg command ?
Look specifically at man page for chvg and the:
-B Changes the volume group to big vg format. This can accommodate up to
physical volumes and 512 logical volumes.
1. The -B flag cannot be used if there are any stale physical
or there are any open logical volumes in the volume group.
2. Once the volume group is converted, it cannot be imported into
4.3.1 or lower versions.
3. The -B flag cannot be used if the volume group is varied on in
4. There must be enough free partitions available on each physical
for the VGDA expansion for this operation to be successful.
5. Since the VGDA resides on the edge of the disk and it requires
contiguous space for expansion, the free partitions are required
edge of the disk. If those partitions are allocated for user
they will be migrated to other free partitions on the same disk.
rest of the physical partitions will be renumbered to reflect
of the partitions for VGDA usage. This will change the mappings
logical to physical partitions in all the PVs of this VG. If you
saved the mappings of the LVs for a potential recovery
should generate the maps again after the completion of the
operation. Also, if the backup of the VG is taken with the map
and you plan to restore using those maps, the restore operation
fail since the partition number may no longer exist (due to
It is recommended that backup is taken before the conversion,
after the conversion if the map option is utilized. Since the
space has been increased substantially, every VGDA update
(creating an LV, changing an LV, adding a PV, and so forth) may
considerably longer duration.
6. A big VG only supports Enhanced Concurrent Capable.
Be aware there was an issue with the chvg command and AIX 5.2...
Also, the big VG is supported when you create the volume group too.
mkvg -B for big
mkvg -G for giant
From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On
Behalf Of cbaker@GOODYEAR.COM
Sent: Friday, December 10, 2004 1:58 PM
Subject: Re: append-only file
We have a two P655s running AIX 5.1 ML 04. Each has 3 or 4
volume groups on them that are using EMC Clariion SAN disks. Each VG is
about 1 to 1.5 TB big. They are made up of hdisks (hdiskpowers) LUNS
that are about 50 GB each. We wanted to add disks to each of these VGs
and, maybe, add a VG to each P655.
Our EMC team presented us with new LUNs that are about 120 GB
each. We thought this would be better since we are hitting the 32 PV
limit on some of the VGs we now have.
When we tried to add one of these new hdiskpowers to a VG that
has 26 PV's already, it gave this error:
Command: failed stdout: yes stderr: no
Before command completion, additional instructions may appear
0516-1162 extendvg: Warning, The Physical Partition Size of 64
creation of 2157 partitions for hdiskpower184. The
limitation for volume group
nfs4vg1 is 1016 physical partitions per physical volume.
Use chvg command
with -t option to attempt to change the maximum Physical
Physical volume for this volume group.
0516-792 extendvg: Unable to extend volume group.
When we tied to change the VG with the command "chvg -t 3
nfs4vg1", we got this error
> chvg -t 3 nfs4vg1
0516-1193 chvg: WARNING, once this operation is completed,
volume group nfs4vg1
cannot be imported into AIX 430 or lower versions.
Continue (y/n) ? y
0516-1160 lchangevg: Volume group conversion is not possible
since the factor value
of 3 can accommodate utmost 10 physical volumes.
0516-732 chvg: Unable to change volume group nfs4vg1.
Here is what "lsvg nfs4vg1" shows:
VOLUME GROUP: nfs4vg1 VG IDENTIFIER:
VG STATE: active PP SIZE: 64
VG PERMISSION: read/write TOTAL PPs: 19016
MAX LVs: 256 FREE PPs: 1024
LVs: 8 USED PPs: 17992
OPEN LVs: 8 QUORUM: 1
TOTAL PVs: 26 VG DESCRIPTORS: 26
STALE PVs: 0 STALE PPs: 0
ACTIVE PVs: 26 AUTO ON: yes
MAX PPs per PV: 1016 MAX PVs: 32
LTG size: 128 kilobyte(s) AUTO SYNC: no
HOT SPARE: no
What are our options here?
Was hopping to move larger disks (LUNs / hdiskpowers) into each
VG and then migrate data over so that I could slowly remove the smaller
disks, but now I am not so sure that will be as easy as I thought.
Is part of the problem because these two servers are still on
AIX 5.1 rather than AIX 5.2? Does 5.2 allow you more than 32 PV in a
If I make new VG's with the new larger disks 1) What should I
be mindful of? 2) Can I then easily move / migrate the contents of
each of these 64 MB PP VG to these newer 256 MB PP VG's?
Thanks in advance for any input you can offer.
Christopher M. Baker
Senior Technical Support Analyst
Goodyear Tire and Rubber Company
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