On Mar 31, 2004, "Prilly" <prilly@xxxxxxx> wrote: > I'm thinking about setting up a software raid level 5. > Is it possible to start with 3 HDs and then later add more? > I mean, without loosing the data on the first 3 HDs. Tricky. My best recommendation for you, if this is your plan, is to partition your hard disks with several relatively small raid partitions, create raid devices out of them, and then make LVM physical volumes out of each raid device. Group the physical volumes into a volume group and then create logical volumes in it as you'd have created filesystems on the raid devices. Leave at least one of the physical volumes unused (or at least easy to free), such that, when you add more disks disk, you can: a) pvmove the contents of one of the active raid devices to the spare physical volume b) take the formerly active raid device out of the physical volume c) raidstop it d) create a new raid device using partitions from the new disks, that should be partitioned similarly e) create a physical volume in the new raid device f) add the physical volume to the volume group g) optionally, wait for raid resync to complete, then pvmove data back to it, rearranging it while at that. Repeat for all other raid devices. It's a bit of a pain, but since all of the above (except perhaps for adding the hard disk) can be done on the live system, it's no big deal, and it can all be easily automated with some shell scripting, especially if you don't care about the exact layout of your logical volumes on the raid devices. -- Alexandre Oliva http://www.ic.unicamp.br/~oliva/ Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org} Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org}
