Why should I use LVM?

[Ernetas]

So... I think that might be interesting topic.
As I know from Wikipedia, LVM is good, because it provides much faster work with partition table. That's right?
Let say it really does. So why should I create LVM partition, while I could create simple one for all Linux stuff? Isn't there any difference between recovering files from LVM partition and from simple?
We are creating partitions for /home, /tmp, /usr and etc. cause we need low loss of files, when any of the file systems goes wrong. LVM gives one partition for many. If I lose one partition so another one will go down too?
Tell me if I wrote something not true.

[jexxie]

LVM lets you create and delete partitions on the fly, doesn't give you a limit of how many partitions you can create, and lets you resize the partition size on-the-fly.

If my /home directory is 90% full, and I want to add 5GB to it, I can. If I'm using reiserfs, I can even do this while the partition is mounted and live.

It's also very easy to create backups via snapshots wit LVM, so that might help you, since you want protection from that.
_________________
Rambling sysadmin
My personal site and blog: Phil Dufault

[Ernetas]

So, actually there aren't any minuses?

[jexxie]

I've heard that you loose about 20% of your disk bandwidth just in overhead, from LVM managing your device(s), but have no numbers to substantiate that claim.
_________________
Rambling sysadmin
My personal site and blog: Phil Dufault

[tld]

I use LVM on my mythtv backend machine, primarily because in mythtv < 0.21 you can only assign one directory for recorded programs. I'm using a logical volume spread over my two 500GB drives for all those HD recordings.

Obviously the downside with that setup is that, if either drive fails, I loose everything...but hey...it's only TV

Tom

[jexxie]

Similarly, you could setup software raid0 to do the same thing, but lvm works as well.
_________________
Rambling sysadmin
My personal site and blog: Phil Dufault