I decided to remove the 80G RAID-0 partition in my PC, and migrate the data inside to other LVM partitions. Currently, the partition has 1 LVM2 vg which contains 3 lvs. One of them contains files I downloaded and the other 2 are /tmp filesystems in my Slackware and Ubuntu installations respectively. I simply copied the files in the first lv to another lv (non-RAID LVM). For /tmp filesystems, I did the following steps for each of them:
- Create a new lv (RAID-1 LVM) of 4G. (lvcreate)
- Format it as reiserfs. (mkfs.reiserfs)
- Mount it to a temporary mount point.
- Copy files in /tmp over using rsync -av
- Go to single user mode and unmount /tmp
- Edit /etc/fstab to change /tmp to use the new lv.
- Remount /tmp and go into multi-user mode.
Note: the device to be put into fstab should be /dev/<vg>/<lv>, not /dev/mapper/<vg>-<lv>.