Warehouse Stripe Size with Oracle8

I am a data warehousing consultant working with Oracle8. I have some experience with Oracle on UNIX, but I'm certainly not a DBA and I'm looking for advice with the following issue:

We are running Oracle 8.03 on a 4-way DEC Alpha under VMS (please don't ask why, it is a long story.) We have over 300 GB of disks, set up in various RAID arrays (RAID 1, RAID 0+1, RAID5).

Our system DBA's set up the Oracle blocksize to be 32K (to oltp folks, that may sound somewhat high, but for data warehousing, it's considered kosher.) The disk arrays were set up with a 512 byte stripe size.

Now, intuitively, the stripe size sounds way too small - I picture the o/s getting swamped performing 64 i/o's to read 1 Oracle block (and in data warehousing, you are reading lots of blocks). Now apparently the disk controllers have a 32 MB cache to mitigate that somewhat, but I've read information (page 58 of Oracle8 Data Warehousing by Dodge and Gorman, Oracle Consulting's Physical Database Design Guide by Rainer Runge) that says the minimum stripe size should be at least 2X the DB_BLOCK_SIZE.

This has been deemed "probably correct in theory" by our VMS team, who are unwilling to change the set up based on anything other than practical experience (they haven't had any problems with 512 bytes in their oltp systems and this is their first encounter with a warehouse.)

Does anybody out there have any "practical experience" with striping an Oracle data warehouse under VMS, or have enough Oracle/VMS experience to refute the recommendations from Oracle and Mssrs. Dodge and Gorman? I'm concerned that proceeding with this set up will burn us and will be a ton of work to "undo".

Thanks,

Howard Galusha

-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Tue Feb 16 1999 - 08:15:20 CST