hi sysadS,which RAID configuration do you have on your servers RAID 10 or RAID 5?
if budget is not a concern is RAID 5 really good? or RAID 10 still better?

Thanks for any input.

Raid10 performance is better or equal. But rebuilding the raid after a failed drive is much faster with raid10. So less change another drive breaks during the rebuild phase. Well with raid10 you lose more space so you need more or bigger drives. The question is then how much costs a lost day.
-raid is no backup solution-

It really depends a lot on your usage of the system, how much you're going to store over how many disks. RAID5 can be harder / scarier (!) to modify, as you need to recalculate all the parity across your devices when going from, for example, 4 disks to 5 disks, which in reality can often lead to inaction from worrying you'll break something!

I generally would prefer a RAID10 style solution, but within a software solution, I wouldn't actually use it as RAID. I'd suggest making pairs of RAID1 disks and using LVM across them, instead of RAID0ing them. you get more flexibility that way, and you could actually go further to use LVM mirroring too, which would give you the logical functionality of RAID10 without any RAID at all.

Actually I far prefer RAID-6 on hot-swap drives over either.

I find average performance of RAID-5 often superior to the average performance of striped, which was not my expectation when I started testing. While RAID-6 is a bit slower than RAID-5, it is nice to shed some worry about outage time if you have a drive fail.

With RAID-6 you can be swapping out a failed drive and have a SECOND drive fail with no downtime.