My rule-of-thumb is to only use LVM when it's necessary, as in providing more file system space than one minidisk can provide. I put /temp, /var, etc. on their own minidisks so that errant processes cannot accidentally fill all the available free space and crash the system. Our LVMs hold databases, so if we need to repair one from another Linux, its just a matter of unmounting the existing LVM, and then linking to the disks that need repairs, in which case identical volume and group names don't matter. Yes simple is much better, especially at 3AM!
Ray Mrohs Energy Information Administration U.S. Department of Energy -----Original Message----- From: Romanowski, John (OFT) [mailto:[EMAIL PROTECTED] Sent: Friday, January 21, 2005 12:05 PM To: [email protected] Subject: Any caveats moving root filesystem to LVM? Anyone have experiences moving root file system to Logical Volume Manager (LVM)? We run SLES8 under VM on S390 with Linux guests cloned from a 2-dasd (3390mod3's) linux image with "/" on one pack and /usr on the other pack. I'd like more flexibility to use the free disk space from each pack as a global pool of free space so I'm evaluating converting the existing Linux file systems to LVM with root file system in LVM. I'm comfortable on how to create the logical volumes and copy the existing Linux file systems into it, but I'm not clear on how the LVM-based Linux will boot up and how I'd "rescue" such systems later if needed. 1) At IPL how will the Suse initrd find the Volume group and mount the root file system? I'm going to change /boot/zipl/parmfile to say "root=/dev/vg/v1" to request the logical volume be mounted as root fs; my /etc/sysconfig/kernel will be coded to load lvm-mod via INITRD_MODULES="jbd ext3 dasd_diag_mod lvm-mod"; and I'll run mkinitrd and zipl. But is that enough to get a logical volume mounted as the root file fs by initrd? 2) After converting to LVM I'll have a bunch of Linux guests whose Volume Group name and logical volume names are identical (as if I'd originally cloned them from an LVM-based Linux image). For rescue purposes, can one of these Linux's CP LINK to and mount another of these Linux's volume groups and volumes given it's already running with the same volume group & volume names itself? Any tips on this are appreciated. ---------------------------------------------------------------------- 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
