For Rendering to Disk only. Checkpoints and recovery are ignored for interactive rendering.
Recovery allows us to resume/recover from the previously paused or incomplete stopped render. To turn it on, use prman -recover 1 in the RenderMan RIS ROP's Command.
If we are not enabling checkpoint, we also need to turn off incremental in the RenderMan RIS ROP.
Render recovery is often used with checkpointing. We can use checkpoint with prman command line, e.g. prman -checkpoint <time or increment> in the RenderMan RIS ROP's Command.
To use more option, we can add the following Checkpoint options to the RenderMan RIS ROP:
Incremental renders are not recoverable without checkpointing enabled. With incremental on and checkpoints off, the buckets are not written out until the end of the render. See table below:
Recovery and 'keepfiles'
Do not enable the keepfiles option for checkpointing if you want to use the recover capability.
Option "checkpoint" "uniform int keepfiles" 
The keepfiles option causes prman to save a sequence of checkpoints for debugging purposes giving each checkpoint image a unique file name tagged with increment and elapsed render time. However, when attempting to recover a file, prman won't scan your directory for checkpointed files or try to choose one. It will only look for the file by the original render output name.