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One way and two way synchronization

In one way synchronization, the target location is changed until it matches the source location. The source is not changed. Files and directories on the target may be created, updated or deleted (with optional archiving of deleted and updated files) until the target matches the source. One way synchronization is particularly useful for creating on line backups of working file systems. With archiving activated, it provides an efficient tool for maintaining both current and historical copies of working files.

In two way synchronization, both file systems are updated, each with changes made to the other. This is particularly useful for users who work on more than one computer - for example a desktop and a laptop - and wish, periodically, to merge the changes made at both ends, so that both computers contain the latest data. Files and directories on both systems may be created, updated or deleted, with optional archiving of deleted and updated files. MirriM is able to resolve many difficult cases; for example if the user deletes some unwanted files on system A, MirriM will delete (or archive) them on system B, so that the two are synchronized. Unlike other synchronization tools, it can distinguish this case from the similar one where files are created on system B, and need to be copied to system A.


A preview window shows all the operations that are required to synchronize the two file systems, and allows you to cancel or modify individual operations. For example, if MirriM thinks a file should be updated on the destination directory by copying from the source directory, you can alter it to copy the other way instead. You can also cancel some operations while allowing others to proceed. When you're ready, just click to finish the synchronization.


MirriM's archiving system keeps copies of updated and deleted files up to a specified number of generations. The "intelligent thinning" option ensures that when the generation limit is reached, recent archives are retained, but a proportion of older ones are deleted - like tape rotation in traditional backup systems.


Mirrim can be run in a non-interactive "batch mode", and batch runs can be scheduled to run regularly using the Windows Task Scheduler. In batch mode, your synchronization jobs are defined in a control file, which you can create and maintain using a text editor, or the normal interactive Mirrim interface.

Synchronize securely over the Internet

MirriM can synchronize computers across the Internet. Just install the MirriM server as a service on either the source or target computer. Then use MirriM as normal on the other; the only difference is that you need to specify the name or IP address of the MirriM server. Mirrim can easily be configured to access servers which are protected by firewalls. MirriM compresses and encrypts communications across the internet (no additional software is needed).

Server option with super-fast file updates.

The Mirrim server uses a sophisticated "sliding window" algorithm for updating files. This ensures that only the changes are sent, and reduces data transmissions to a tiny fraction of what would otherwise be required. In many cases, it is quite practical to use a dial-up connection to maintain offsite backups. The following bar chart shows the speed increase MirriM can give when updating.

Bar Chart
MirriM is created by Polyhedron logoPolyhedron Software Ltd.