SATA Raid

[Christopher Browne]

On 6/19/06, CLIFFORD ILKAY <clifford_ilkay-biY6FKoJMRdBDgjK7y7TUQ at public.gmane.org> wrote:
> As I explained above, I already have decent RAID cards, which I
> disable and subsequently use software RAID because it seems that
> kernel support for even popular cards can change without warning. My
> motivation clearly isn't cost since I already own the cards. Besides,
> I have seen all sorts of batteries fail. What makes the battery
> backup for your RAID card any more reliable than a UPS?

The on-card BBU does not need to depend on the entire chain:
  UPS -->
      Power Cable -->
         PSU -->
            Motherboard -->
               CPU, RAM, ...

It shortens the chain to:
  Battery --> RAID Cache

The failure of *any* of the components in the first chain will corrupt
the filesystem.

In the case of the RAID card with BBU, *none* of those are forcible
dependancies.
-- 
http://www3.sympatico.ca/cbbrowne/linux.html
Oddly enough, this is completely standard behaviour for shells. This
is a roundabout way of saying `don't use combined chains of `&&'s and
`||'s unless you think Gödel's theorem is for sissies'.
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