I know how RAID work and prevent data lost from disks failures. I want to know is possible way/how easy to recover data from unfunctioned remaining RAID disks due to RAID controller failure or whole system failure. Can I even simply attach one of the RAID 1 disk to the desktop system and read as simple as USB disk? I know getting data from the other RAID types won’t be that simple but is there a way without building the whole RAID system again. Thanks.
You really do not want hardware raid. You want software raid like LVM or better yet, ZFS.
Do your own research. Keep in mind raid isn’t a backup. It is only for convenience.
A lot of “hardware raid” is just a separate controller doing software raid. I thought I lost access to a bunch of data when my raid controller died, before I realized that I could just plug the disks directly into the computer and mount them with mdadm. But yes, hardware raid seems a bit pointless nowadays.
In my experience, using spinning disks, the performance is very poor, and times for scrub and resilver are very long. For example, in a raidz1 with 4x8TB, scrubbing takes 2-3 weeks and resilvering takes almost 2 months. I must also add very poor performance in degraded state. This is a very old post, but things are still the same.
