Failures of various RAID modes.

dbott67 wrote:

The level of RAID that one chooses is a balance between price, performance, capacity and availability/resiliency. If you need higher availability/resiliency (especially on larger arrays) then you should use a level of RAID that can tolerate multiple disk failures. Of course, this decreases capacity or increases price (or both) but it generally increases performance. There are other factors that can cause data loss that RAID does not protect against (i.e. some other sort of hardware failure, accidental or intentional deletion, malware such as cryptolocker, fire/flood and theft). Additionally, there are other factors that would need to be addressed if high-availability were paramount (redundant power supplies, redundant network links, NICs, UPSes, etc.) My big sermon is always to maintain multiple backups in multiple locations. Keeping only one copy of your data on a single device is not a backup. Having another copy of your data stored elsewhere will always allow you to recover in the event of a disaster.

I totally agree.

I'd also add that high-availability is usually much more important to business users than it is to home users (since taking the business systems off-line will reduce both productivity and sales).