Question about BE restore

Hi,

I have question about BE restore.

If server crashed, there are 2 ways to restore system.

1) SDR by recovery disc

2)  reinstall OS then restore "complete online restore of a computer, or restore system components"

-------------------

- Which option is faster ?

- For SDR recovery, is BE recovery disc is a must ?

- Since tape drive is using for backup, SDR recovery will point to get recovery data from tape drive ?

Thanks