Best disk RAID configuration for Oracle 8.0.X OLTP Data Base

[Omar Torreblanca V._1]

Hi,

Now i have an Oracle's instance resident on HP4000 server. To day the data are on HP Surestore XP512 with RAID 5 configuration. Any idea who are the best RAID configuration for OLT? Data Bases, RAID 5 or RAID 0 + 1?

Thanks in advance for your comments.
OTV.

[hpuxrox]

On an XP I would say Raid5. Now, EMC works better with Raid0+1 or what they call Raid-S.

But I have no benchmarks to prove, This is just what I have been told.

[MANOJ SRIVASTAVA · Accepted solution]

Hi Omar

It depends on the $$ you want to spend , incase you want a cost effective and better through put and redundancy then RAID 5 is the the best thing , hoever if you have $$$ then Raid 0+1 will be the solution . Please not that in bothe cases the response time would be same but in case of RAID 5 if you ahve moer than one disk going down then the data is gone however this is very rare.

Manoj Srivastava

[hpuxrox]

By standard convention RAID0+1 is much better than RAID5 as far a preformance, but I have been told that this is not true for XP's. XP's are designed for RAID5 and are suppost to be much faster than its EMC counterpart.

We can go round and round on this performance issue. Because there are some many diffrent varibles involved.

[Andreas D. Skjervold]

Hi

What Oracle themself recommend these days is SAME; Stripe And Mirror Everything.

Andreas

(I miss OFA!)

[Roger Baptiste]

hi,

From what i have seen ,
If you are using EMC symm, go for RAID 0/1.
IF Xp512, go for RAID5.

WIth EMC, you can also use Metavolumes (which spreads luns across physical disks ,thereby giving an additional level of striping).

Physical disk config is only part of the solution. The lv stripe size should be set appropriate to your requirements. I normally set the distributed 1Mb extend and it works well.


HTH
raj

[Vincent Fleming]

With XP512, there are many things to consider in picking your RAID level for OLTP...

Generally, RAID-5 on an XP will outperform RAID 0/1 in most cases, except for small block random writes, where RAID-5 is about 15-20% slower. In most databases, this is hardly noticable.

Compared to EMC's RAID-S, (which is rated by EMC at 15% of the performance of RAID-1), the XP's RAID-5 is viable alternative with about 85% (overall) the performance of RAID 0/1.

A more important choice is drive size. It's faster when you keep logs on the 18GB/15k drives. RAID-5 is OK for logs because it's mostly sequential writes, which are highly optimized in the XP.

RAID-0/1 is suggested in databases where you have a high insertion rate - use them for indices and dataspaces, as your budget allows. Insertions into the database cause small block random writes.

Cache is another important item. Adding more cache can significantly increase your performance.

80-90% of all XP's out there (about 4000 now!) are running 100% RAID-5. Most all of them are used with databases.

Good Luck!

[Tom Danzig]

Vincent:

I see you're with HP. Is the staement:

"80-90% of all XP's out there (about 4000 now!) are running 100% RAID-5. Most all of them are used with databases."

Is this a fact that can be backed up with data? Just curious as I may have to justify my use of 100% RAID 5 on my XP512 for multiple Oracle DB's.

Thanks,
Tom