On Monday 20 February 2006 11:51, [EMAIL PROTECTED] wrote about 'Re: Re: [gentoo-user] raid/partition question': > As an extension of this question since I'm working on setting up a > system now. > > What is better to do with LVM2 after the RAID is created. I am using > EVMS also. > > 1. Make all the RAID freespace a big LVM2 container and then and then > create LVM2 volumes on top of this big container. > > or > > 2. Parcel out the RAID freespace into LVM2 containers for each partiton > (/, /user, etc.).
3. Neither. See below. First a discussion of the two options. 1. Is fine, but it forces you to choose a single raid level for all your data. I like raid 0 for filesystems that are used a lot, but can easily be reconstructed given time (/usr) and especially filesystems that don't need to be reconstructed (/var/tmp), raid 5 or 6 for large filesystems that I don't want to lose (/home, particularly), and raid 1 for critical, but small, filesystems (/boot, maybe). 2. Is a little silly, since LVM is designed so that you can treat multiple pvs as a single pool of data OR you can allocate from a certain pv -- whatever suits the task at hand. So, it rarely makes sense to have multiple volume groups; you'd only do this when you want a fault-tolerant "air-gap" between two filesystems. Failure of a single pv in a vg will require some damage control, maybe a little, maybe a lot, but having production encounter any problems just because development had a disk go bad is unacceptable is many environments. So, you have a strong argument for separate vgs there. 3. My approach: While I don't use EVMS (the LVM tools are fine with me, at least for now) I have a software raid 0 and a hw raid 5 as separate pvs in a single vg. I create and expand lvs on the pv that suits the data. I also have a separate (not under lvm) hw raid 0 for swap and hw raid 6 for boot. I may migrate my swap to LVM in the near future; during my initial setup, I feared it was unsafe. Recent experience tells me that's (most likely) not the case. For the uninitiated, you can specify the pv to place lv data on like so: lvcreate -L <size> -n <name> <vg> <pv> lvresize -L <size> <vg>/<lv> <pv> The second command only affect where new extents are allocated, it will not move old extents; use pvmove for that. -- Boyd Stephen Smith Jr. [EMAIL PROTECTED] ICQ: 514984 YM/AIM: DaTwinkDaddy -- gentoo-user@gentoo.org mailing list
