Can't vgreduce

[Justin Willoughby]

There is a disk that is part of the one of my volume groups that can not be removed. It does not seem to have any logical extents in use by any LVs but still shows extents in use. I am thinking I will need to do a vgexport and re-import not including the disk. I just want to verify this is what I should do. I did some searches on the fourms here and it kind of sounds like this is what I have to do. Anyone else have this problem and have to do the same thing? c1t3d0 is the disk I am going to vgreduce out.

pvdisplay -v /dev/dsk/c1t3d0

--- Physical volumes ---
PV Name /dev/dsk/c1t3d0
VG Name /dev/vgname
PV Status available
Allocatable yes
VGDA 2
Cur LV 0
PE Size (Mbytes) 4
Total PE 9416
Free PE 9250
Allocated PE 166
Stale PE 0
IO Timeout (Seconds) default
Autoswitch On


--- Physical extents ---
PE Status LV LE
0000 free 0000
... all the way to ...
9415 free 0000


- Justin

[Pete Randall]

Justin,

It appears to have some 700MB still allocated. Go through the logical volumes with lvdisplay -v and see if you can find one with extents on /dev/dsk/c1t3d0.

Pete

[Ken Hubnik_2]

Run this

vgdisplay -v /dev/vg00 | grep c1t3d0

for all your vg's

[Justin Willoughby]

I checked and can't find any. I just saw another post with the subject "PV falsley showing allocated PE's" that seems to describe about the same problem. pvdisplays 0 LVs. I will keep looking. I did not schedule enough time for two reboots and I am removing this disk this weekend when the system is down.

I may try and vgchange -a n && vgchange -a y and see if that makes any difference or not once I shut down the application that uses this the VG.

- Justin

[Justin Willoughby]

Ken,

Only one of my VG has this disk as part of it. But none of the LV's are on this disk (according to lvdisplay). Very strange...

--- Physical volumes ---
PV Name /dev/dsk/c1t3d0
PV Status available
Total PE 9416
Free PE 9250
Autoswitch On

- Justin

[John Poff]

Hi Justin,

I'm not sure how to fix it. Was c1t3d0 ever part of an LVM mirror? I wonder what would happen if you mirror an LV between two PVs, break the mirror, and then do an lvremove on the lvol? Would LVM know to go free up the PEs on the second disk after the mirror has been split?

JP

[Pete Randall]

Justin,

Maybe the vgchange will "wake it up" - we can hope. If it doesn't you might want to try physically disconnecting then using vgreduce -f. From the man page on vgreduce:

The vgreduce command with -f option removes all missing physical
volume from the volume group.

That sounds like just the ticket.

Good luck,
Pete

[Pete Randall]

Justin,

Actually, further reading makes me have doubts about vgreduce -f :

"-f vg_name force reduction of missing physical volume(s) in a
given volume group. This option does not require
a physical volume (PV) to be supplied on the
command line. vgreduce obtains the name of each
physical volume (PV) belonging to the volume group
from the file /etc/lvmtab. It then reads the LVM
structures from each PV and compares these with
that held by the kernel to work out which PVs are
missing. PVs which are missing will be candidates
for removal. If all the physical extents on the
missing PV are free then it will be removed from
the volume group. Otherwise vgreduce will report
the physical to logical extent mapping. For
missing PVs, which have extents in use, you must
free up all the extents by using lvreduce(1M) or
lvremove(1M) and re-run vgreduce with the -f
option. This option is most commonly used when
the vgdisplay(1M) command shows "Cur PV" higher
than "Act PV" and all of the PVs belonging to the
volume group are attached. This option only works
on PVs and not on links.


Your vgexport idea is sounding better all the time.

Pete

[Justin Willoughby]

John,

The disk was part of the volume group at one time. I did a mirror/break for all LV's to new disks (on a SAN). When I was done I went to do a vgreduce of the disk and could not.. This is where I am now. There were two disks I moved data off of and one I could vgreduce just fine, it showed 0 extents in use. The other disk showed extends in use but now where.

Should I just do the vgchange -a n && vgchange -a y then vgexport/import or what about doing a vgscan, would that do anything for me? The disk I am trying to remove is from a LUN on a AutoRaid 12. I don't see the LED flashing so I assume there is do data being access (still on the AutoRaid).

- Justin

[Justin Willoughby]

Fortunately I did not need to do a vgexport and re-import of the volume group Sunday morning. The system was showing extents in use (which were not in use and the system could not tell me where they were in use at). I first tried a 'vgchange -a n vgname' and then 'vgchange -a y vgname' to de-active and re-activate the volume group. This cleared the problem with the system thinking some extends from the AutoRaids were still in use. I was then able to vgreduce the AutoRaid out of the volume group.

Thanks to all who replied!

- Justin