RAID 5 VS RAID 10 for home NAS
 

So you (or I as it were) are building a home NAS. You have a case that holds 4 SATA drives, any size. Focusing on data preservation/recovery over performance/size which would you pick and why? (It might also be helpful to note that I’m attempting this with openfiler linux so I’ll either be formatting the disks with ext3 or XFS.)

RAID10 is superior to RAID5 because it can survive 2 disks failing at the same time whereas RAID5 can only survive one failing.

However, with only 4 disks other things come into play:
1) It seems you'd be more likely to lose the right 2 disks at once.
2) If you use all 4 for the RAID set you won't have hot spare. This means you'll be at risk (especially in RAID5) until you get the new drive replaced so you need to know how long that will be and if you're comfortable with that.

Raid 10 can support more failures ad stated above. It's also faster and typically deployed for database applications. As another alternative you can look at raid 6 which is similar to raid5 but can sustain 2 simoltaneous disk failures.