Snow Leopard has come out with 10.6.2
Doing OS upgrades (ie Leopard to Snow Leopard)
Do I need to disconnect Drobo or DroboPro before performing operating system upgrades?
Yes, please do disconnect Drobo or DroboPro before performing any upgrades on its host computer. An operating system upgrade can cause file corruption and/or data loss. Installing applications such as Boot Camp or Parallels can also present similar risks.
Before performing an OS upgrade (for example, XP to Vista, Leopard to Snow Leopard, or even 10.5.7 to 10.5.8), please put your Drobo or DroboPro into standby mode. Then disconnect the data cable (USB, FireWire, or iSCSI) to prevent any possible file corruption.