Performance with one Sun T3 disk array

Does anyone have any REAL experience using a single Sun T3 disk storage array for a "small" Oracle server? How does the performance compare with a "practical" SCSI/RAID1/OFA configuration with control files, redo1, redo2, archived redo, rollbacks, data, index on seven or so distinct sets of mirrored spindles.

The server will be a two processor Sun E420R or E450, 2GB RAM, Oracle 8.1.7. The workload will be light OLTP during the day, so we will be running in archive log mode. I expect any disk system will handle the daytime load, but there will big (20GB+) reloads of data at night and on weekends that concern me. These big loads might be direct inserts (no redo) or they might not. I'd appreciate comments on both direct and "standard" load performance.

By default, the T3 array comes configured as a 9 disk RAID5 array. The T3 array for this server will be half of a T3ES partnered pair, if that makes any difference.

The jist of my question is: Sun and my hardware guys tell me the adaptive write cache algorithms on the T3 raid controllers are good enough to collect the redo, archive, etc etc writes and perform them efficiently enough to equal (or at least approximate) the performance of dedicated spindles for each writer. This is including the overhead of maintaining the RAID5 parity.

I am skeptical. They are confident. Should I believe them or not?

Just so we don't waste alot of bandwidth here, let me state up front: 1) I don't need a lesson on RAID, or the evils of RAID5 in "standard" scsi arrays for high transaction load database servers. I already understand Oracle OFA guidelines about distributing write processes across spindles etc.

2) I have already read the thread "Performance problems with Oracle EE 8iR2 on 64 Bit Solaris" on this news group from 12/18/2000, which is closely related to my question.

3) This is a "small" system with a single T3 array, not a huge system with 20 T3 arrays, each of which is assigned to an individual write process. I already know that works well.

Thanks in advance,

John Beckerle
O'Brien Database Consulting  

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