Hello,
I'm planning on rebuilding my currently running NAS system, but struggle to decide which way to choose with storage and possibilities.
My running NAS includes 2x 4 TB and 1x 6 TB harddrives independently to each other. For backups I use two external HDDs and rsync. The really important stuff (about 500 GB) is saved on another machine, too.
For my new build I decided to get a useable capacity of about 20 TB.
My first thought to achieve that was a 3x 12 TB combination running in an RAID 5 array. After some further thoughts on that I don't think that this config really would be reasonable, due to the large disk capacities and high stress a rebuild on RAID 5 would come with to the other drives... It seemed that RAID 6 or 10 could be an alternative, but require 4x 12 TB drives.
Summarizing the pure disk prices and the fact that I would still need a backup (at least for the important data) I started to completely discard the thought of RAID usage.
An alternative I see would be the use of 2x 20 TB HDDs, so that I could possibly use RAID 1 to create two redundant drives (as a kind of "first level backup"). Important files would be backed up to external HDDs stored offsite.
My question here is, if this would be a meaningful config or if there is a better alternative. I was thinking of the possiblity to add disks in the future, so the RAID 1 would be bad for this use case. Could a MergerFS pool on a single drive, which is used in RAID 1, later be expanded with another single drive and its RAID 1 redundant copy?
The only usage I had for RAID in the past was for small business operation, so I don't know, if I may be overthinking this whole topic for my home NAS...
MergerFS and SnapRAID, that seem to be quite popular in combination, I did not use yet, so I cannot classify them fully.
Thank you for your help!