[lug] LVM and disk failure

[Tony Dyson]

> Absurdum infinitum: suppose you created a volume group out of 1000 RAID-1
> pairs.  Now if you put a logical volume spanning the whole volume group, and
> one RAID pair dies for whatever reason, the whole thing is gone.

Only for a certain value of "dies". If one disk of the pair fails & you 
are aware of this, replace it promptly & a mirror rebuild occurs, you 
haven't lost any data.

If data security is your priority, ignore LVM & think about RAID. For 
peace of mind use hot-pluggable hardware RAID; RAID-5 for maximum 
capacity, or RAID-1+0 for best I/O performance. Either way, "hot spare" 
disks are a Good Thing.