Re: modifying a vg in 11.11

Super Advisor

modifying a vg in 11.11

Hi experts,

OS -11.11

vgdisplay /dev/vgxxx
--- Volume groups ---
VG Name /dev/vgxxx
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 5
Act PV 5
Max PE per PV 6399
PE Size (Mbytes) 4
Total PE 31991
Alloc PE 31991
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

The follwoing disks are currently use.

The VG vgxxx has set the Max PE per PV=6399 and the PE size=4.It means that this VG can be increases only by (6399MB*4) 25GB per Disk.One of my friend added 200GB lun(c18t5d0) & he is able to use 25GB only...we are missing 175 GB.

I Have the following solution,Can you please check whether it is correct or not.

1.Take a full backup of the Filesystem of this vgxxx.[done by backup team]
2.vgexport -p -v –s -m /home/ -f /home/vgxxx.dsk /dev/vgxxx
3.unmount the FS
4.Deactivate the vg vgchange -a n /dev/vgxxx
5.vgexport /dev/vgxxx

6.Recreate the vg

ll /dev/vgxxx/group [to get the minor no]
pvcreate /dev/dsk/c18t5d0 [200GB disk]
mknod /dev/vgxxx/group c 64
vgcreate -p 150 -l 100 -s 4 -e 51200 /dev/vgxxx /dev/dsk/c18t5d0 /dev/dsk/....[alternet path]

-e [will be use for Max PE per PV right? --200*1024=204800/4=51200]

lvcreate -L 128000M -n lvol1 /dev/vgxxx [Making a lv of 125GB]
newfs -F vxfs -o largefiles /dev/vgxxx/rlvol1
mount /dev/vgopenv_tmp/rlvol1 /oraarch

then I will do the pvcreate & vgextend for remaining 4 old disk.
pvcreate /dev/dsk/c16t2d6 [size is 25GB]
pvcreate /dev/dsk/c16t4d1 [size is 25GB]
pvcreate /dev/dsk/c16t4d2 [size is 25GB]
pvcreate /dev/dsk/c16t4d3 [size is 25GB]

7. After that backup team will restore it.

Please let me know am i correct.

James R. Ferguson
Acclaimed Contributor

Re: modifying a vg in 11.11

Hi Ani:

Your procedure looks good. However, remember that when you do your 'vgexport' at step-5 that the device files will be removed. Hence before the export, make note of the volume group minor number you want to reuse.


melvyn burnard
Honored Contributor

Re: modifying a vg in 11.11

You could log a call with the HP Response Centre and ask for the uinsupported tool known as vgmodify.
This may help you
My house is the bank's, my money the wife's, But my opinions belong to me, not HP!
Jayakrishnan G Naik
Trusted Contributor

Re: modifying a vg in 11.11

Hi Ani

Can I assume that you are doing this; only because you need to utilize the bigger lun (125G) in this vg?

You do the full backup of the filesystem, that is fine, but Why you need to create a map file?
At step 6, you are creating a new vg by scrapping all pvs, so what is the relevence of step 2?

step 3 4 5 looks fine, But at step 6 you are running ll/dev/vgxxx/group to see the minor number. But you cannot find this at that stage as vg is already exported at step 5. If you need to use the same minor number for new vg, check it initially before exporting vg, i.e. before step 5 .

And about the vgcreate command, Is there any restriction for you to use the extend size as 4MB (-s 4)? What about setting higher extend size of 8M or 16M or 32M?

These are what I can find to highlight here.

Thanks & Regards
jayakrishnan G Naik

Jayakrishnan G Naik
Trusted Contributor

Re: modifying a vg in 11.11

Hi Ani,

As updated by Melvyin, if you have vgmodify tool you can avoid the extra work of backup, vgrecreation and restore. But being 11i V1 version, I am not sure how you can get it installed and used, better follow Melvyn's suggestion to check with HP.

Thanks & Regards
Jayakrishnan G Naik
Super Advisor

Re: modifying a vg in 11.11

at the time of work i will remember all those which you have mentioned. Thank you.