[CentOS] to lvm or not to lvm - why/when to use lvm

Hi,

I was wondering, why/when it is useful or when should I avoid to use LVM.

I think the big advantage of LVMing is if you modify (rezising, ...) disk and filesystem layouts "a lot".

Are there any real pros or cons for following situations regarding e.g. management and speed?

e.g.:

I do have a server system raid for which the disk layout will not change; e.g. /var /usr /home will not change much in size.

OR

I do have some file storage shares (iscsi raids) up to some TB each on one big storage device.

Sometimes (e.g. after a server crash) it is useful to remount the storage to a different server.

Should I use LVM on the iscsi storage volumes?

Any suggestion and comment is welcome . Regards . Götz