


Backblaze publishes their report about every quarter. You can look for disk reliability data published by heavy commercial users. 2 other sources for information about disk drives to consider So I would stick with drives labeled for use as internal desktop drives (not RAID or NAS drives) unless you have assurance that the drive does not use SMR. What is worse is that it can be hard to tell if a drive uses SMR because some manufacturers fail to disclose this. Long story, but those devices perform fine when used as Time Machine backups until Time Machine starts pruning old files, at which point they perform quite poorly. One thing to be careful about, especially with high capacity drives, are drives that use Shingled Magnetic Recording (SMR, DM-SMR). 2 Drives also allows you to keep one off-site, which can be critical if your computer and backup drive are both stolen, destroyed in a fire, or suffer some other common catastrophe just due to being in the same place at the same time. To help ensure they do not both fail at the same time, I recommend buying drives from 2 different manufacturers. Expect they will both fail at some point, just hopefully not at the same time. Buy 2 drives and alternate backups between them.Something like the Hiachi Western Digital Ultrastar. Get one designed for 24/7 server use with a 5 year warranty. As Apple did with Time Capsule, you buy a single rugged drive that is unlikely to fail.Beyond that there are 2 schools of thought: Maybe use the 120 GB drive for downloads or something.Īs for what kind of drive to use for Time Machine, definitely get a 3.5" Hard Drive (best value), and I recommend getting bare drives plus a dock rather than drives in an enclosure, again because you get better value that way. Maybe you could use a tool like Carbon Copy Cloner to keeps some important documents backed up to it, but really you should be using Time Machine. Your 120 GB drive is nearly worthless at this point. APFS is optimized for SSDs and runs poorly on spinning platters, so format your 120GB drive as HFS+. That will make a noticeable speed improvement over using a magnetic disk. Format your SSD as APFS and use it as your boot drive.
