RAID 10 for oracle database

[sheevm]

Hi,

We are in the SAN planning for oracle database server.
Based on the previous experience I think RAID 10 is the best configuration as far as the performance and the redundancy. I just want to confirm this.

The reason is one of my peer said in the RAID 10, because of the striping table and the index could be in the same spindle.

Please comment and give your thoughts.

Thanks
RajiM

[Pete Randall]

Here is an excellent guide to the different Multiple (Nested) RAID Levels that may help you:

http://www.pcguide.com/ref/hdd/perf/raid/levels/mult.htm


Pete

[Steven E. Protter]

Shalom,

For a write intensive database.

Data
index
redo logs

Should be raid 1 or raid 10.

Raid 5 for heavy write databases cause long i/o wait times because the actual data is written to more different portions the disk.

Second reason makes no sense to me, but the reasons above make it clear that raid 10 is good.

I have no problem with raid 5 for data mines and applications that don't write often or heavily.

SEP

[Alzhy]

Ahh one of the "it depends" question.

The rule these days is to test and compare RAID5 and RAID0+1/1+0. You will be surprised the gap has narrowed down a lot and RAID5 now actually is an excellent layout vis a vis the balance between capacity, redundancy and cost.

In most of my implementations, Overall Application performance difference do not exceed 10% between RAID0+1/1+0 implementations and RAID5. This has been true for cache-centric arrays and certain controller-centric arrays like the EVA and the Clarion.

If 10% improvement does not merit the additional costs (reduction of storage capcity) of RAID0+1/1+0 implementations - go for RAID5.

[sathish kannan]

Hi RajiM,

I would say, it depends your IO patterns. Usually RAID 10 is good for write and RAID 5 is good for your read activities. If your oracle application is read intensive (ex Oracle financials), RAID 5 may give little bit advantage than RAID 10.

With SAN, it is very difficult to say how many spindles are mapped to the LUN. So my advise on SAN environment is, to create LUNS on maximum spindle to take advantage of more spindles and share across multiple backend disk arrays.

Regards
Sathish

[f. halili]

We use RAID 1/0 for Oracle Database. For the application itself Raid 5 will do.

If you will follow what Oracle recommends for number of spindles and which goes to which. You'll end up with dozens of disks to fulfill the requirement.

There is another concept that you can find in Oracle best practices - SAME ( Stripe And Mirror Everything ). There are people advocating this technique. Bottom line on this one is - have as many spindles as you can get and put them in RAID 5.

Cheers,
f. halili

[Kenan Erdey]

hi;

for EVA, in vraid1, writing to mirror is done asynchronously, so no latency happens. writing to database means generally random writes. in raid5 random writes causes double data transfer to mirror ports because of parity. except performance criters, vraid1 supplies more redundancy to store your data.