Keeping tradition with doing things backwards, I've finally got a UPS for the rack (mounted in the bottom of the stack). Got a PowerWalker VI 2200R. Its a 2U unit which is all the space I've got left in the rack. Decent price and decent I/O with USB, serial and a slot-in for network expansion + 4 IEC outputs. Its powering everything in the rack and connected via USB to my main server which runs a NUT server that other machines can connect to. A calibration run (100-80%) puts the runtime at about 20 min. Long enough that I'm comfortable setting things to shut down when 20% capacity remains. Summary, I sleep better now.
Back when I built racks, our "standard" was UPS at the bottom, all drives at the top...but mainly for accessibility. Hadn't even thought about vibrations or interference!
Ups at the bottom is also because of the weight of the batteries. In a small rack like this I don't think moving the disks 30cm up will make a big difference.
Absolutely on that point. Same goes for heavy multi zone amplifiers.
Man I loved building racks. Almost makes me miss field work...
Drives at the top? Hell no. SANs are heavy, they go in the bottom half too (assuming a mixed rack). Especially if you have those disk shelves that slide out so they hold 3.5" drives three deep. Top of the rack is for network hardware and such.
I did not install SANs, I built racks for AV so the only drives were NAS/mini PCs on shelves