LVM Mirroring r1 (See the current copy)
Linux LVM Mirroring Sucks
I'm using the ability of Linux's Logical Volume Manager (LVM) to mirror data on to two drives. It's horrible. It requires either a third disk (which can't be the same disk as either of the two components of the mirror, but can be a software RAID (Linux MD) of both disks), or to resynchronize at every boot (using "corelog").
Additionally, it has been reported that if a physical volume (PV) is missing, any volume group (VG) using that PV is "read-only" and any logical volumes (LVs) are also "read-only". This means that you cannot use the mirror in degraded mode (it can be mounted "read-only", which is not too useful).