Here’s OpenZFS Mastery on physical labeling. I have strong feelings on this.
Develop a consistent naming and numbering scheme for your storage arrays, and use it dogmatically. Many storage arrays have a standard naming scheme, often printed on the equipment. If your equipment already has numbered shelves, use that numbering. Otherwise, make simple rules like “shelf 0 is always at the top and disk 0 is always at the left.” You might use the prefix “f” for the front and “b” for the back, or whatever works for you.
Record the serial number of each drive as you install it in the array. Physically label each drive tray with the drive serial number and physical location. Use good labels that remain stuck over years of being ignored in a dry, dusty datacenter. Yes, this is tedious—but when a drive fails you must have this information. You can do this work in peace and quiet at your own pace, or you can desperately rush through it during an artificially prolonged, unnecessarily stressful outage.