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Re: Anybody use HP AutoRAID with an Oracle DW?

From: Mark Weghorst <weghorst_at_nilenet.com>
Date: 1998/07/02
Message-ID: <6nh496$gja$1@thoth.nilenet.com>#1/1

MCR (mrush_at_hertz.bogus.com) wrote:
: Does anyone have any experiences or recommendations regarding the use of : HP's AutoRAID with Oracle8 for use in a Data Warehouse?

Well I haven't used in a DW environment, but I do have experience iwth it in an OLTP application.

When I first used one of the 12H arrays I was very wary of "Autoraid," it made me very nervous that I couldn't control the layout of the array at a low level like you can with the nike array's (Data General Clariion's OEM'd to HP). After my first project though, I love them. They are real easy to set up, and wicked fast too. I'd only get a 12H though and not a 12, that way you can have the array controllers with 96MB of cache each. My setup was somewhat like this:

	HSC FWD SCSI			HSC FWD SCSI
	|				|
	|				|
	|				|
 12H 96MB Array Controller	12H 96MB Array Controller
	|				|
	|---------------Mech1-----------|

|---------------Mech2-----------|
|---------------Mech3-----------|
|---------------Mech4-----------|
|---------------Mech5-----------|
|---------------Mech6-----------|
|---------------Mech7-----------|
|---------------Mech8-----------|
|---------------Empty-----------|
|---------------Empty-----------|
|---------------Empty-----------|
|---------------Empty-----------|

The Autoraid array attempts to keep all of your data in RAID 0+1, but when your array is over 50% full it has to move some of the data to RAID 5 for disk space. It uses a LRU caching algorithim to determine which data should be in 5 and which to keep in 0+1. The key to good performance with a 12H and Oracle is to keep it less than 50% full. One of the coolest things about the 12H is that it stripes every read and every write across all of the present disk mechs in the array. Every disk mech is accessable to both controllers, so it's kind of like having twice the number of mechs for the same price. The caching controllers coordinate between one another enough so that I never noticed contention for the same mechs. I suspect that when HP/UX commits the writes to the disk, it's stored in the array controller and the array writes it to disk at it's leisure (I have no proof of this). I usually set up primary and secondary IO pathing, so that controllers A & B each have thier primary IO path on a seperate SCSI bus.

I've had better luck with the reliability of the 12H's than I have with the 10/20/30 nike arrays. The only array that I like better is the Sun A5000, but that's a very different animal. They are two extremes of the spectrum, they both perform great, but one is easy to setup but inflexible, and the other is infinitily(sp?) configurable to the extreme.

I've heard rumors of a FCAL interfaced Autoraid, but I haven't seen it myself. From what I heard, the mechs are still SE scsi but the interface between the host and the array is FCAL.

Also the 12H array has just become officially supported by HP under NT, which is great news. That way after the pilot project on NT fails you can just keep your array and use it on your new HP/9000.

Good luck with your decision. One of the best things about HP, is that if you are really unhappy with something they will make it right, even if means they have to take the 12H back and let you trade it towards a Nike. Make friends with your local field office, it's well worth it. The local offices have helped me part the waters of bs many times to get a customer's system squared away. In fact, I found them so helpful that when I worked for a HP/9000 VAR I made it standard practice to always have the local rep come over to meet their newest customer at some point during the system deployment.

-Mark Weghorst Received on Thu Jul 02 1998 - 00:00:00 CDT

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