Conventional online file backup technology is based on batch processing on a fixed
schedule. Although there have been incremental improvements over the years, limitations
in the fundamental design persist to this day.
Some of the key limitations are:
Backups are executed nightly or at another scheduled interval, so that files on the
backup system are always a day, or at best hours, out of sync with the files on the
At the whole backup level, backup programs, such as rsync in UNIX or Linux, search
and compare the entire local and remote directories to find out which files have
been updated since the last sync. This time-consuming process wastes I/O cycles and
CPU resources and can slow down any system significantly.
At the file level, the process also need to compare the local file and the remote
file, instead of recording updates, even if only small changes are made.
Twin Peaks' Mirror File System technology can overcome these limitations because
it takes a completely different approach:
When a file is created or updated on the primary system, the update is replicated,
in real time, to the same file on the backup system.
Only the portion of the file that has changed -- the update -- is replicated. There
is no need to compare the local and remote files to replicate the changes, especially
where large files are concerned. Replicating only the updates frees up system resources
and network bandwidth.
With real-time backup, primary and backup systems are always in sync, and neither
time nor data is lost.