Trying to wrap my head around the differences between RAID5 and RAID6. It floats around a lot that RAID5 is advised against, and there are always comments saying "it's ok in a 3 drive setup" etc. and that it's mostly not recommended for larger arrays.
I currently have a 4 bay NAS with 3 drives set to RAID5 (or SHR). I have an external drive for backups and setting up my offsite backup next week. If a drive starts to fail, my plan is to use the empty bay to copy everything from the dying drive, rather than performing a database rebuild.
Overall I'm not that concerned about dual parity for the meantime because ~~if a second drive dies that's my excuse to get a bigger setup~~ my hope is to catch the failing drive early, and I've got backups to fall back to. To be honest I think I'll have a bigger setup before I start seeing failures anyway.
However, something I've been trying to wrap my head around is data scrubbing. This looks at the data on the drives against the parity and checks for errors. If you have two parity drives, does that mean you have more accuracy during data scrubbing? Because now it has two points of reference?
Just making me wonder if I should consider filling the 4th bay and set to RAID6 (SHR2) for better data scrubbing.