I have a few HDDs that I intend to use for data backup. The projected use case is a full overwrite of contents every month or so, and I intend to read only in the event of data loss on my primary memory units.
I want these drives to last as long as possible, which is why I plan to only keep the drives connected when I want to write and evaluate health. In my mind, this prevents degradation while protecting from edge-case power surges and device theft. Is this strategy going to do anything to extend lifespan, or am I better off keeping the drives plugged in?
The TrueNAS gods say to leave HDDs plugged in and spinning.
The current way to store digital data is as “living data” with backups. Data only exists if it’s constantly verified to exist. You can’t verify an unplugged HDD. Of course, you need a 3-2-1 backup system, and have to continually verify those backups as part of the living system.
The magnetic platters in a HDD are actually decently reliable. Sure a cosmic ray or error may flip a bit, but that’s why we have backups and redundancy elsewhere in the system. That flipped bit won’t actually damage the hardware.
The real concern with HDDs is that they mechanically wear out and break. They stop spinning. The motors malfunction, the lubricants dry up, the metal bearings wear down, etc.
TrueNAS says the most dangerous time in a HDDs life is when it is spinning up or slowing down from a stop. This gives the most mechanical stress on the HDD. They says it’s better to leave them powered and spinning 24/7 than to unplug them or despin them.