Mirror imaging

I set up my 2 drives on my 2TB Sharespace to be mirror copies. Does anyone know how that works? does it write simultaniously to both drives or is there a scheduled back-up? Which drive am I actually working off and can I easily retrieve info from the second drive?

If you chose for the Sharespace to set the drives up as RAID 1, then, yes, the same data is being written to both drives simultaneously.