Not a dumb question! If you're talking about spinning rust, this is precisely the job of some particularly niche sysadmins (the kind that manage storage clusters) to know. I'm not one of them, but a quick search produces this:

https://serverfault.com/questions/13839/does-orientation-aff...

The easier answer I'm comfortable giving (despite me not being a sysadmin by trade) is that good storage software/setups should abstract over and protect you from something like this, because SSD/HDD bit-rot is absolutely a thing regardless of orientation -- if you're not using a WAL-ing (ex. zfs) or checksuming (ex. ceph's Bluestore) file system you're exposing yourself to data corruption. Only thing left is whether you'll actually have your drives long enough for them to exhibit complete failure from orientation, can't know that except to test like Backblaze/other providers do.

Common wisdom is that it doesn't matter, but you shouldn't change it. Anecdotally drives that ran mounted vertically that then are moved to horizontal mounts do have increased failure rates.

The general consensus is that drive orientation does not matter.

Makes sense to me, the parts are fixed, they're not heavy, gravity does not affect them.

However I've not seen anyone test this in real life.

FWIW I've only ever had drives mounted horizontally, the normal way and upside down. All of them had about the same lifespan.

Somebody might be able to correct me on this but I believe that BackBlaze's vaults use vertically mounted drives, so that might be some useful data to apply to answer that question.

BackBlaze was not alone (not sure who was first) to mount drives vertically. Xyratex did that in the near-line storage units (e.g. RS-4835), as did Hitachi and others. Once you've seen them, it's the obvious choice to maximize the number of 3.5" drives in a rack (~48drives in a 4U chassis). Heavy beasts though -- you want a lift to mount them.

Don't know about relative reliability to horizontal mounts, but afair the drive manufacturer recommends mounting either vertical or horizontal and we didn't observe any obvious issues.

BackBlaze publishes good data, although I suppose that other manufacturers (such as Dell) make storage appliances with vertically mounted drives thats a data point that they at least think its okay-ish.

If Andy is watching this thread, I'd love to hear if he explored this topic previously.

For what it's worth, a bunch of server OEMs sell top-loading storage servers, eg. https://www.servethehome.com/dell-emc-poweredge-xe7100-100-d...

Please, Backblaze, for science, install some racks lying on their side. :)

no. Vibrations while it runs matter. Do not put it next to speaker.