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Photos are courtesy of Liang Hong

 

 

Online File Backup

 

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 primary system.
• 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.