Rather than rewriting Microsoft's backup and restore guidelines, we have chosen to direct you to the official documents and then to summarize some key points. Note that some of the documents were written for MIM's predecessor, FIM, but still hold true:
Backup and Restore Guide for FIM 2010 (http://bit.ly/MIMBackupRestoreGuide)
FIM CM Backup and Restore (http://bit.ly/MIMCMBackupAndRestore)
FIM Reporting Disaster Recovery (http://bit.ly/MIMReportingRecovery)
SCSM Disaster Recovery Guide (http://bit.ly/SCSMDisasterRecoveryGuide)
High availability and PAM disaster recovery (http://bit.ly/MIMPAMDisasterRecovery)