How to resize a PV located on a SAN LUN

Hello,

since a few weeks we have an IBM SAN environment with Blade-Center. The SAN controller is a DS4700 formerly known as FASTt. We have a LUN with 200 GB of size. The LUN ist partioned:

fdisk -l /dev/sda

Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1         125     1004031   83  Linux
/dev/sda2             126       26108   208708447+   5  Extended
/dev/sda5             126         188      506016   83  Linux
/dev/sda6             189        1185     8008371   83  Linux
/dev/sda7            1186        1435     2008093+  83  Linux
/dev/sda8            1436        1560     1004031   83  Linux
/dev/sda9            1561        1810     2008093+  83  Linux
/dev/sda10           1811        2060     2008093+  83  Linux
/dev/sda11           2061        4053    16008741   83  Linux
/dev/sda12           4054       24960   167935446   8e  Linux LVM
/dev/sda13          24961       26108     9221278+  82  Linux swap

Now i had to increase the size of partition of sda12 which is a LVM. I am not sure which is the right way. Within the storage managment software i can increase the size of the LUN. After rebooting the machine the additional space is appended at the end of partitions and it is marked as free. How can i now increase the LVM partition. Which tool/programm i do need for this task?

Best regards,
Micha

Who the hell is General Failure, and why he is reading my disk?

hi,

why would you want to do that? if your vg is running out of free extents, why not just add a new LUN from the SAN and extend the vg with it?

you can't really increase the physical volume, because there's a swap partition between your physical volume and the free space. use fdisk to partition the free space as /dev/sda14, create a physical volume on the new partition (pvcreate /dev/sda14) and extend the volume group with the new physical volume (vgextend yourvg /dev/sda14).

hth,
tom.

Thomas "Duke" Hager                       {duke,hager}@sigsegv.at
GPG: 1024D/D27F858C            http://www.sigsegv.at/gpg/duke.gpg
=================================================================
"Never Underestimate the Power of Stupid People in Large Groups."

Maybe, because their SAN configuration get bloated with smaller LUNs? When SAN enables extending size, why not use it?

As it's swap partition, he can recreate it. So create new swap partition /dev/sda14 at the end of extended disk. Then mkswap /dev/sda14, swapon /dev/sda14, swapoff /dev/sda13. Delete /dev/sda13, add size to /dev/sda12 using fdisk. Then use pvresize /dev/sda12 (it'll autodetect new size). And after this, you can see free PE in vg.

Or better, if you can disable swap partition for some time, switch it off, delete sda13, resize sda12, pvresize sda12 and create new LV for swap inside VG. With this, next time you add some space, you won't move/delete swap partition, just resize(fdisk) and pvresize sda12.

Hope this helps,
PeS

The easy way would be to create a new partition to use that free space, then use pvcreate to make it a physical volume and then add it to the volume group. This would mean you'd have two physical volumes on the device belonging to the same volume group.

Michael T. Babcock
http://mikebabcock.ca

Others have suggested what is probably your only option if you're stuck with this configuration, i.e. create a new PV and add it to the volume group.

This configuration seems a little strange to me. How come you partitioned the LUN this way? Using LVM for everything would have been much more flexible in general.

If you had created a single PV from the whole LUN and created Logical Volumes for each "partition", you would not have any problem now: You would be able to simply do a "pvresize" then "lvextend" to grow the LV, then resize2fs (assuming ext[23]).

Louis