[CentOS] LVM & Softraid & expansion

Sun Apr 1 20:17:07 UTC 2007
Morten Torstensen <morten at mortent.org>

John R Pierce wrote:
> In IBM AIX (where LVM kinda came from), the soft raid and volume 
> management is rather tightly integrated, but in linux, its seperate.

There is not RAID in AIX LVM, just mirroring (well, stripes too but 
never mind that). Since you just map Logical Partitions to multiple 
Physical Partitions (same as Physical Extents, PE, in the linux 
implementation), it is easy to duplicate logical volumes to different 
physical volumes. You can do this online of course, as it is all below 
the filesystem/logical volume level. Migrating from one SAN to another, 
one disk to another, adding disks, splitting disks, removing disks. All 
is done in the LVM. As it should be.

The linux approach is much more primitive. Too bad the linux lvm guys 
used HP-UX LVM as their reference.

-- 

//Morten Torstensen
//Email: morten at mortent.org
//IM: Cartoon at jabber.no morten.torstensen at gmail.com

And if it turns out that there is a God, I don't believe that he is evil.
The worst that can be said is that he's an underachiever.