[Info-vax] RAID vs. MOUNT/BIND

[Phillip Helbig---undress to reply]

In article <ic1esf$lgs$1 at pcls6.std.com>, moroney at world.std.spaamtrap.com
(Michael Moroney) writes: 

> 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.

OK, right, of course.  Replace RAID 0 with RAID 5: same question.

> 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.

OK, so here one can do only the right thing.  :-)