Using the vxrsync utility, you can perform three different operations; full synchronization, difference-based synchronization, and data verification.

When performing full synchronization between volumes the utility copies all the data from the source to the destination volumes. For performing difference-based synchronization, the utility first calculates the checksum and then compares the checksums between volumes. Based on the result the utility copies only those blocks that have changed on to the target volumes.

When performing verify data operation, vxrsync first calculates the checksum for the volumes to find the change in data between the source and the target and then displays the difference on the console.

The vxrsync utility consists of two components, vxrclient and vxrserver. The vxrclient must be running on the source computer and the vxrserver must be running on the target computer. Note that the vxrserver must first be started before the vxrclient is started. The vxrclient and the vxrserver require either volume names, the RVG name, or a configuration file name as input. You must also specify the port number on which the vxrserver needs to listen for requests. If you use a configuration file as input, then, the port number that you specify for the vxrserver must be the same as that specified in the file. If no port number is specified for vxrserver, then, by default, it uses the port number 8989 and vxrclient uses this port to communicate with vxrserver.

If you choose to use the RVG name as input then you must ensure that the target or Secondary (RLINK) must be detached. Make sure that the target volumes are not in active use during the period the synchronization or verification is in progress. Otherwise, the synchronization process fails. If the -x option is specified with vxrclient then the source volumes are locked. Otherwise, a warning message is displayed, but synchronization still proceeds.

Also, note that all the specified volumes with the same names and sizes must be present on each host within the RDS.

The configuration file defines the relation between the source and target volumes which need to be synchronized or verified. If you want to use the configuration file as an input then you must first create it. Ensure that the file is created using a text editor and is available in the current directory from where you are running the command.

The configuration file can be used both for synchronizing the data volumes or for verifying the data. However, for the utility to complete the specified operation successfully, the configuration file must be exactly the same on the source and the target. Blank lines and lines starting with a # character are considered as comments.