A couple of years ago I built a TrueNAS system, the host is a SuperMicro Server with an HBA connected to a 45-bay SuperMicro JBOD. When I built the server I bought 38 20TB Manufacturer Recertified EXOS drives from Serverpartdeals. I put 36 of them in the JBOD and setup 4 Raid Z2 VDEVs with 9 drives in each VDEV. I also put 2 drives into the host itself and set them up as Hot Spares. I am at the point of needing to start contemplating adding additional storage. Would it be best to buy another 9 20TB EXOS drives of the same model and add another VDEV with those, or should I buy 9 larger EXOS drives and add the fifth VDEV with the larger drives? How would that work with the Hot Spares that are only 20TB if one of the larger drives fails? Should I buy 10 of the larger drives and add one of them as a spare so if a drive fails in that VDEV it uses the larger spare? Also, serverpartdeals seems to have gotten pricier, the 20TB drives are $60 more than when I bought them nearly two years ago, are they still the recommended place for picking up cheaper recertified drives or are there better options?
You can pick any size you want for the new vdev, but spares have to be large enough to fit in any vdev.
Thank you, sounds like I should just get more 20TB EXOS drives then so they match with the SPAREs