Configuration of Oracle datafiles on disks

[Theodore S. Feldman]

I have read "OPTIMAL STORAGE CONFIGURATION MADE EASY" by Juan Loaiza, Oracle Corporation and "Configuring the Oracle Database with VERITAS Software and EMC Storage for Optimal Scalability, Mangeability, and Performance," published by Veritas. According to these white papers, Oracle, EMC, and Veritas now discourage configuring storage of Oracle database files by placing them on different sets of disks. Instead, they advocate "SAME": Stripe And Mirror Everything. On modern storage systems with caching, asynchronous reads/writes, etc., you just stripe across all disks, separating by partition if necessary rather than by disk.

I would appreciate comments on this approach. Has anyone tried it; what has your experience been?

Thanks!

[Alexander M. Ermes]

Hi there.
Equipment :
V2500, EMC 3430 with 96 disks in raid level 1
( means 48 filesystems with 860 GB net disk space ).

Running 25 Oracle databases.
Distributed thru all filesystems on EMC according to performance. You should place the files on several disks. If you have files for tablespaces, which are highly used, keep them away from filesystems with online or offline logs or controlfiles. If you create reports to be printed and logged, keep these files away from the others, because they might disturb each other, if large transactions take place.
That also goes for TEMP or ROLLBACK tablespaces. Make a nice plan on an Excel sheet, how to spread the files thru the file systems. That will help. If you use fiber channel connections to your disk arrays, check the load on the different channels to do some load balancing.
I hope, this helps a bit.
Rgds
Alexander M. Ermes

[Praveen Bezawada]

Hi
We have an application which uses three filesystems on three 17GB disks.
Our experience has been that when we have all the 3 disks in a single volume group and then have 3 different logical volumes for each filesystem we get a better performance when compared with having 3 volume groups with one logical volume each on different disk and one file system in each logical volume.
Hope this info helps...

...BPK...

[Thomas Yake]

I have a similar configuration on an 8730. I am creating new filesystems that are based on striping several lvols across a large volume group.

[Deshpande Prashant]

Hi
If you are using EMC disks, try the EMC software power path which will do load balancing between different paths to EMC disk, besides providing fault tolerance. This software also allows you to define policies for using multiple paths.

Thanks.
Prashant Deshpande.