I noticed that RAID 5 has been used for a lot of critical application such as SQL server machine. However RAID 10 seems to be a lot more robust. But not much people using it. Any reason why or when should we consider RAID 10 or never?
migrated from stackoverflow.com Mar 1 '12 at 4:08
closed as not a real question by Zoredache, Ward, MikeyB, Shane Madden, Mark Wagner Mar 1 '12 at 7:04
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This question will depend greatly on your hardware, server workload and storage capacity.
For example, Raid 10 can have considerable performance increases over Raid 5 (especially on random or small writes), but storage capacity is cut in half. The performance differences may not even be noticeable depending on the load, so the Raid 5 with the extra space may be more appealing.
Let's assume we have 12 1TB hard drives. In a raid 5 we would get:
Downsides to Raid 5:
Now take 12, 1TB hard drives in a raid 10:
For me, if I am on the fence between a 10 or 5 then I usually go with a RAID 50. This is a good balance between the two (cards that support Raid 50 can get expensive though).
Again, a lot of variables will go into performance on these things: quality of the raid card, speed of the drives, number of drives in your pool, disk/strip alignment in databases, etc.
As mentioned before, most go straight for RAID5 due to cost issues. I use RAID10 for my small setups at work due to them being easier to recover if something goes wrong. If more than one disk goes, there is nearly 0 chance of recovery. With RAID10, for files at least, you have the ability to recover partial bits when things go wrong.
+1 for the BAARF above.