Timing of replica creation
During the export phase, the mkreplica command locks the VOB and dumps the VOB database.
The VOB is locked for the entire length of time the command runs. While the VOB is locked, read-only operations can occur in the VOB, but write operations cannot. (For example, these operations fail: checkins and checkouts, chepoch –actual commands, label creation, builds, imports of update packets, VOB snapshots, and scheduled backups.)
Therefore, you must plan the export phase of replica creation during nonbusiness hours for your site. You must also cancel any scheduled jobs for exports, imports, VOB snapshots, and backups for the duration of the export phase.