The positive part of adding the extra complexity comes when you want / need to expand one of your logical volumes. This can be done via LVM fairly easily, and in some cases, without even taking the filesystem offline. A real, physical minidisk can't do this at all; you need to create an entirely new disk, and copy the data from the old one to the new one. Then, you have to replace the old one with the new one, possibly requiring the guest to be brought down.
The other bad thing about avoiding LVM is that you are then limited by the size of your largest physical disk. If all you have are 3390 mod 27's, then you avoid your users when they need more than 22gig in a filesystem. We have several filesystems on 3390 DASD that are half a terrabyte or larger, and would not be possible without LVM. -- Robert P. Nix Mayo Foundation .~. RO-OE-5-55 200 First Street SW /V\ 507-284-0844 Rochester, MN 55905 /( )\ ----- ^^-^^ "In theory, theory and practice are the same, but in practice, theory and practice are different." On 8/13/08 11:06 AM, "Rob van der Heij" <[EMAIL PROTECTED]> wrote: > On Wed, Aug 13, 2008 at 5:50 PM, RPN01 <[EMAIL PROTECTED]> wrote: > >> Current standard here is to have /boot as a physical volume, root, var, tmp >> and some swap (yes, we're moving to v-disk swap) in LVM vg_system on one >> 3390 mod 9 and /home and /opt in LVM vg_local on a second 3390 mod 9. There >> are pluses and minuses to having root in the LVM, but nothing tips the >> scales greatly either way... > > I think that standard was inspired by experience on platforms where > folks have just a single big disk rather than the option to create > block devices as they like them. I understand the motivation to > separate things in different disks, but to first bundle block devices > in an LVM VG and then create LVs out of that, is a bit odd. It creates > two additional layers of storage management that have a negative > impact on performance and probably complicate things a lot. > > I strongly believe in separating application and operating system. And > there's good reasons to have some things like /var and /tmp in > separate file systems. But you can do with mini disks. Using the > "first-aid" system approach, enlarging file systems on mini disk is > not harder than with LVs > > Rob > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
