[Info-vax] RAID vs. MOUNT/BIND

[Ken Fairfield]

On Nov 17, 12:45 pm, moro... at world.std.spaamtrap.com (Michael Moroney)
wrote:
> hel... 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.

Additionally there is the practical matter that
it takes far less time to shadow copy in a
replacement disk for striped shadow volumes
than it would to shadow copy a whole stripe
set...  Also, less time with (potentially) diminished
performance and less time at higher risk due to
less redundancy (while the shadow copy completes).

   -Ken