question about LVM

[James Murtagh · Accepted solution]

Hi,

Well from my point of view, taking the question literally the answer is false. Can the lvol replace a disk in the diskinfo command for example? That obviously is not how the question was intended, hence I agree with Sri's point - this is totally ambiguous.

The only thing I can think of is before lvm you used to partition disks using the sector convention, i.e. /dev/dsk/c0t0d0s0 which would be replaced by /dev/vgXX/lvol1 in lvm. In this case lvm does take over.

I would complain at the exam if I was given that with no context!

Cheers,

James.

[Massimo Bianchi]

Because it's more efficent.

back to hard sectioned disks, a FS can reside only on 1 disk, at most.

So, if you have a 2G disks, your bigger FS can be of 2G.

With LVM, you group the space togheter, in a VG (volume group) and use it at your needs.


Let's suppone that you have 5 disks of 2G.

You can decide to create 1 logical volume of 10G, or 1 logical volume of 4 G and a 2G logical volume with 2 mirror copies for reduncancy, or you can create 1 Gb logical volume, and take the remaining space free for future needs.


With OnlineJFS you can even increase the FS size online, without rebooting in single single user/maintenance mode.


You can mix the space from many different storage.


Substantially, lvm gives you the power of elevating from the phisical layer and think only at the space, without taking care of phisical layout and limitations.

Massimo

[fishjuli]

thanks all for your reply.

[fishjuli]

James, I agree with you.

[Dave Wherry]

Sri,
Regarding your P.S., I'm not sure I see a problem with this question being posted here. The forum is not meant to be a replacement for the Response Center, for a person in need. There was a question and several people stepped up to answer it. That's what the forum is about.
Points were also assigned. Can it get better than this?