[Info-vax] RAID vs. MOUNT/BIND

[Michael Moroney]

helbig at astro.multiCLOTHESvax.de (Phillip Helbig---undress to reply) writes:

>With host-based RAID, do I have the option of a) binding several small 
>shadow sets into a larger RAID 0 device or b) shadowing two (or more) 
>RAID 0 devices?  If so, which is better?

The wisdom is to make stripe (RAID 0) sets from shadowsets, not shadow
stripe sets. This is due to failure possibilities. One failed drive in a
stripe set takes out the whole stripe set.  If you shadow two stripe sets,
two failed drives (one in each stripe set) takes out the whole thing.  If
you stripe shadowsets, two drive failures can still take out the whole
thing, but only if they both are part of the same shadowset.

The same logic would apply to volume sets, if you decide to go that route,
however you actually don't have a choice since you can't shadow volume
sets, just its members.