We used a single ethernet port/connection and the four 4TB NAS HDD drives that Seagate provided set up in SimplyRAID mode, which enables complete data recovery if a single drive fails. A second SimplyRAID mode enables complete data recovery if two drives fail, but this mode requires an 8-disk array which is of course not possible with a 4-bay enclosure.
SimplyRAID allows multiple volumes to span/share a drive, which makes it easy to expand the array without losing data even when the array contains mixed-capacity disks. Seagate's 4-bay NAS also supports RAID 1, 5, 6, and 10 as well as JBOD (just a bunch of drives accessed sequentially).
In short, the Seagate 4-bay NAS is a good-looking, good-performing box offered at a competitive price.
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