Re: XP256 Disk Striping for an Oracle 8.1.7 DataWarehouse

lewis_uk_at_hotmail.com (Tom Lewis) wrote in message news:<6d8d2ec4.0107120349.37cc7615_at_posting.google.com>...

Given that the disk array is large, I think you also look at the following:

1. How many fibre channels are going to the array?
2. If all the drives are equal speed?
3. How large your e-cache (disk array cach) is?
4. How many Host adapters your machine has?
5. How the Oracle SGA is configured?
6. Is I/O balanced across the array?

The company I am working for also has a large dataware house (1 T Bytes) on the same disk array. If your warehouse is complete, I would recommend going to one
of HP's capacity/benchmarking centres to get the best configuration for both the O/S and I/O.

> I have a 400GB Oracle 8.1.7 data warehouse deployed onto a XP256. The
> warehouse often needs to full table scan tables of c50GB and uses
> parallel execution to achieve this. The database is using 8K blocks
> and the DB_FILE_MULTIBLOCK_READ_COUNT is set to 16.
>
> The XP256 has been configured with RAID 5 and a stripe size of 256K.
> Its 36 disks have been divided into 8 logical volumes of 4-6 disks
> each with different tables or indexes assigned to each logical volume
> to avoid contention.
>
> I really need some help on two fronts.
>
> What is the optimal relationship between the DB block size and the
> stripe size. Currently, I assume that the database will read 32 blocks
> off disk 1 and then 32 off disk 2 etc. etc. That does not sound very
> parallel to me. Should the stripe size be smaller?
>
> Secondly, is it necessary to divide the XP256 into different volumes
> for different purposes or is a larger single volume a better approach?
>
> Many thanks in advance
>
> Tom
Received on Fri Aug 03 2001 - 09:18:23 CDT