Re: Re: Re: Fast Inserts and Hardware Questions - Mailing list pgsql-general

From Steve Wolfe
Subject Re: Re: Re: Fast Inserts and Hardware Questions
Date
Msg-id 001501c0ae66$e5b7d060$50824e40@iboats.com
Whole thread Raw
In response to Re: Re: Fast Inserts and Hardware Questions  (Alex Howansky <alex@wankwood.com>)
List pgsql-general
> Yes, it is RAID-5 on the big box. Unfortunately, I don't have any spare
RAID
> equipped boxes sitting around, so I can't experiment with the different
RAID
> levels. Still, you'd think that even a "slow" RAID-5 configuration would
be
> faster than a $98 IDE drive...

  Yes, it certainly should be.  Right now I have a Mylex 170 in my machine
for testing, hooked to 4 IBM 9-gig drives.  Three of them are in a RAID 5
array, the last is a hot-spare.  Copying data from the IDE drive to the RAID
array, the IDE drive reads at full speed, the lights on the RAID array just
blink quickly about once per second.  The controller has 64 megs of cache on
it, but I've copied far larger data sets than that (several gigabytes), and
the behavior has been the same.

  So... yes, RAID 5 is slower than RAID 0 or 1 for writes.  But it's still
dang fast, especially compared to a single IDE drive.

steve



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