RAID5 + spare vs. RAID6 (simple)

[enewmen]

Which is better, RAID5 + spare or RAID6, for LARGE drives >= 3tb in a NAS environment.
I can see rebuilding a drive for more than 1 day to be a problem. More so during light use.

thanks!

 

[tomatthe]

Either case you are losing 2x in parity or parity + spare. I would go with the Raid 6 if using 3Tb drives based on the possibility of a drive failing in a Raid 5 set while rebuilding which would leave you with a broken array. Depending on the amount of day on the array it could very easily take over a day to rebuilt if you lose a drive. I'm not sure what type of hardware you will be working with, but generally you can give the rebuild process a prioritization so that it either rebuilds quicker, or the data set is more responsive during the rebuild but it takes longer to complete the repair.

 

[enewmen]

Best answer selected by enewmen.