Hardware Raid Expansion and LVM

[Roberto Ragusa]

Seann Clark wrote:
> 
>    I am looking for a little help on finding out the best way to do
> this. I had a 4 disk 1.4TB RAID 5 array, and extended that to an 8 disk
> 3.18TB array, on a 64 bit system.The Raid card handled the migration of
> the disks well, and everything on that side is up and running as it
> should. Problem is I don't know how to extend LVM to a larger size,
> without doing the whole adding of physical drives, and so forth, and the
> pv display doesn't show more than the 1.4TB that I started with. Most
> documentation details software RAID procedures that don't really work
> with this. I figure I am doing something(lots of things) wrong.

Have a look at the thread called "lvm resizing and shifting" (23/8/2008).
The issue is similar and my proposal worked in that case.
Your problem is that you have a 3TB disk (sdb) containing just
a 1.4TB partition (sdb1, which is your pv).

I obviously have to recommend to be very careful when doing these
operations. You have a backup of your data, right?

I'm also a bit concerned about the fact that you will break the 2TB
per partition barrier; I don't know if that limit has been totally
removed nowadays.

Alternatively, you can add a sdb2 and then pvcreate, vgextend, lvextend.

> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] 20971519 512-byte
> hardware sectors (10737 MB)
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] Write Protect is off
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] Write cache: enabled,
> read cache: disabled, doesn't support DPO or FUA
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] 20971519 512-byte
> hardware sectors (10737 MB)
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] Write Protect is off
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] Write cache: enabled,
> read cache: disabled, doesn't support DPO or FUA
> Oct  9 11:58:39 haruhi kernel: sda: sda1 sda2
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:0: [sda] Attached SCSI disk
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Very big device. Trying
> to use READ CAPACITY(16).
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] 6814820353 512-byte
> hardware sectors (3489188 MB)
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Write Protect is off
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Write cache: enabled,
> read cache: disabled, doesn't support DPO or FUA
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Very big device. Trying
> to use READ CAPACITY(16).
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] 6814820353 512-byte
> hardware sectors (3489188 MB)
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Write Protect is off
> Oct  9 11:58:39 haruhi kernel: sd 0:0:0:1: [sdb] Write cache: enabled,
> read cache: disabled, doesn't support DPO or FUA

The important information is just the line you have not included
(sdb: sdb1, sdb2?).
What about /proc/partitions?

Best regards.

-- 
   Roberto Ragusa    mail at robertoragusa.it