Certainly any drive produces some level of vibration, and that vibration can then be carried to other drives through the physical drive trays or frames in an array. The concern is that vibration can force the afflicted drive(s) to reseek and reposition before a read/write operation -- even cause read/write errors. In extreme cases, excess vibration can adversely affect a drive's reliability. This was particularly notable in low-cost ATA and SATA drives with extremely high storage densities.
Remember that this only relates to "normal" operating conditions. If you put the disk array on an airplane or truck, you'll absolutely need to take added measures to minimize shock and vibration when the drive is in use. In those extreme cases, you might opt for hybrid drives or even full solid-state drives instead of traditional magnetic hard drives.
Go back to the beginning of the Disk Hardware FAQ Guide.