On Wed, Jan 21, 2009 at 8:13 PM, Ron Johnson <ron.l.john...@cox.net> wrote: > > If I have lots of existing data in JBODs, would I create a PV and VG on the > new drive, mv all the data from the existing drives to the new VG, then add > my existing drives (while also enlarging the fs) to the one-drive VG, thus > making an uber-device?
That is how I started and how I've been, more or less, running with LVM for years, though I think I'm about to change. First, I've actually had different FS with different settings for different purposes. Mostly different bytes-per-inode for file system that have lots of big or lots of small files. Some have ext2 vs ext3 differences. Some are backups of retired windows machines that are just readonly. And i'd do the occasional snapshot to do backups from. As each FS would fill up, I would extend that particular FS. Some would reach a steady state. One interesting side affect of this is the fact that I would fragmentation at the filesystem level, as opposed to the file level. Every once in a while, I'd move LVs around to defrag (usually as part of adding a newer larger harddrive, and retiring the smaller one). One pain point I have is this: In order to run resize2fs(8), you have to fsck the FS first. As they grow larger and larger, this takes longer and longer. I have a 2TB FS now that I really don't want to grow any more because of that. Ext4 may solve the fscking issue, but in the one article I've read so far, resizing wasn't mentioned in it. (I'm also considering ext4 for other reasons.) One thing I do tend to do with every disk is this: I put a small swap partition on each disk, then the rest is an LVM partition. Depending on the machine, it could be 128M to 256M; I try to stay consistent across disks. I then set up each swap partition with the same priority. That way I get more spindles in action for swap. I have really no idea if it makes a difference or not, but it's something I do. It may very well actually cause more contention because if I'm doing something that is causing me to page, then I'm probably processing data on all of those disks anyway. Anyway, that's my experience with LVM. I like it, I've used it for, mmmm... I'm not sure how long I've used it... has it been around for 10 years? I can't remember when I switched to it, but I'm pretty sure it was before I moved to the South Bay Area. It took for years of lobbying to get folks to start using it at work for one service I'm responsible for; down time for backups dropped from one hour to one minute, since they can now do LVM based snapshots and bring the service right back up. mrc -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
