Generally, it is. The initial spike of electricity does the most damage. In addition, a sitting drive can eventually see the lubricants settle and stick. Once the drive is spinning, there is virtually zero friction wear. That said, a drive spun up once every several months will likely have a very long life for storage as long as the lubricants were manufactured correctly. I still have old ~500 MB drives that still work. The main advantage of having them run 24/7 is you are likely to register warnings before the drive completely dies, giving you an opportunity to decide how to deal with it. A sitting drive can simply not start up again. Plan accordingly.
Couldn't you implement a strategy of replication and tiering to reduce wear across all drives? Some drive groups could be put to sleep and an infrequent event, like the failure of another node or disk group, would then cause these drives to spin up.
I know it’s a little different, but AWS Glacier doesn’t keep all data “hot”.
