Overview of Replica Creation


You use this three-phase procedure to create a new replica:

  1. Export: At one site, enter a mkreplica –export command, which creates a new replica object and a replica-creation packet.
  2. Transport: Send the packet to one or more other sites.
  3. Import: At the other sites, enter a mkreplica –import command, which imports the replica-creation packet.

The procedure is similar for different methods of packet delivery and for different platforms. The example in this chapter assumes that you have a high-speed connection between hosts, and that all replicas are located on UNIX machines. The procedure is the same if all replicas are located on Windows machines or if one replica is on a Windows machine; only the VOB tags and pathnames are different.

If some replicas in a family will be located on UNIX machines and others will be on Windows machines, be sure to read Replicating a VOB Between UNIX and Windows.

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 need to schedule the export phase of replica creation during nonbusiness hours for your site. You must also cancel any scheduled exports, imports, VOB snapshots, and backups for the duration of the export phase.