Using SolVe online is the best way to get the procedure. It gives us a step-by-step procedure based on each Isilon model.

Alternatively, we can use Dell Technologies on-line support site and search "Isilon Drive Replacement".

Isilon S210 and X410 Hard Disk Drive Replacement video also helps us understand the procedure.

[FYI]
You can access to the below document even if you don't have a Dell Technologies on-line support credential. 
Isilon Generation 6 F800/H600 Replace a drive