[Gllug] Hardware comparisons

[Nix]

On 24 Mar 2007, Martin A. Brooks spake thusly:

> t.clarke wrote:
>> Sorry,  I am curious - what are the merits of having a battery-backed up
>> cache on the RAID controller ?
>
> That's the only safe way to be doing write caching.  Sensible RAID
> controllers don't let you turn it on unless there's a BBU present.

Even without write caching, unless the disks are spindle-synched you can
silently corrupt data in a stripe that's being actively written to when
the power fails, unless you have a battery backup to complete the stripe
write when the power comes back on (and spindle-synching is as far as I
know dead because it's so costly).

-- 
`In the future, company names will be a 32-character hex string.'
  --- Bruce Schneier on the shortage of company names
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