Re: Is Raid 5 really that bad for Oracle?

"omlet" <notrolls_at_notrolls.omlet.org.notrolls> wrote in message news:<c1298bcca272850daa05252529d5fd7d_at_localhost.talkaboutdatabases.com>...
> My argument is this:
>
>
>
> 4. But the RAID level 5 array is deficient in a number of important ways
> (performance degradation during partial outage as Howard mentioned,
>
> Dead wrong! all the rebuilding done in the background using SMP and tons
> of cache reserved for this -- by the way SCRUBBING is done all the time in
> all major arrays; and during partial outage is not degrading more than
> Daniel Morgan.

That may be true on some boxes, but from what I've seen it is user-noticeable fairly quickly, even those not near saturation to begin with.

>
> worse read performance [contrary to popular belief],
>
> Now where the hell did you get this?! I have spent more than 6 years
> benchmarking and running tpcc code on Storageworks, Symmertix and Filers:
> the magic word you missed here is prefetching. Actually you yourself
> published the sequence of blocks Oracle data files are accessed; and
> prefetching breaks only for random access patterns; so simply use index
> only tables with contigeous overflow storage and you get a perfect match!
>

Oh, that must be your view-skew: you are taking an unrealistic benchmark and trying to knot reality to it. "simply use index only tables" indeed! LOL!

jg

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