Chapter 8. LVM 2 Boot Time Scripts

For initrds, you should have:

dmsetup mknodes vgscan --ignorelockingfailure vgchange -ay --ignorelockingfailure

in the linuxrc to get the root LV activated before the root volume is accessed. Most distros seem to have this setup in their mkinitrd scripts now, and they also tend to have them in rc.sysinit or equivilant, so all volumes get activated on bootup.