Comment by Youden

I use RAID6 because it gives me highly efficient utilization of my available storage capacity while still giving me some degree of redundancy should a disk fail. My workload is also mostly sequential, so random read/write performance isn't too important to me.

If a disk fails and resilvering causes a cascading failure, I can restore from a backup.

I think you might be mistaking RAID for a backup, which is a mistake. RAID is very much not a backup or any kind of substitute for a backup. A backup ensures durability and integrity of your data by providing an independent fallback should your primary storage fail. RAID ensures availability of your data by keeping your storage online when up to N disks fail.

RAID won't protect you from an accidental "rm -Rf /", ransomware or other malware, bugs in your software or many other common causes of data loss.

I might consider RAID10 if I were running a business-critical server where availability was paramount, or where I needed decent random read/write performance but even so I'd still want a hot-failover and a comprehensively tested backup strategy.