Thanks for the question, Guillermo.
Asked: September 25, 2019 - 11:15 pm UTC
Last updated: October 02, 2019 - 1:52 am UTC
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Hi, according with the note 30286.1 i see that the raid5 is not recommendable for some files like redos, archives, and datafiles, at this time i have 2 disk arrays one array in raid 5 at 15,000 rmp and the second one is a raid1 array at 10,000 rpm, today all the files are inside the raid5 15,000 rpm but the performance is too slow, i am thinking about move my database at the raid1 at 10,000 rpm but i don´t now if these results in slower performance per the slower disks, even when i have a fastest raid.
What would be your recommendation in order to get a better performance?
and Connor said...
I think the vast majority of literature out there nowadays on RAID is out of date, because of the advancements in disk technology, flash and memory.
For example, most NetApp storage appliances use RAID-6, and can manage huge levels of performance.
If you do have just a very simple JBOD with no caching etc, then RAID-5 will have a small *write* performance penalty.
So I'd recommend:
a) first, quantify if you have a write or a read performance issue (or both), because RAID-5 will not impact *Read* performance (unless disks have failed).
b) your redo files are sequential write only, so will typically not get much benefit from any kind of RAID level besides mirroring for protection
But generally, the easiest way is to look at moving to ASM where we'll default to striped and mirrored for everything and you'll be close to optimal performance without needing to micro-manage the storage.
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