RSYNC vs. Image-Level Backups
Backups are most important when you really need them. Most hosting companies, business and personal users implement their backups with traditional RSYNC. Since RSYNC can be piped over SSH it serves as a very secure way to perform backups of critical files. Using Rsnapshot can provide even more flexibility with snapshot capabilities.
What if you have thousands of files? What about millions of files? RSYNC becomes very cumbersome as it has to walk every directory and every file to compare checksums, modified times and contents. RSYNC literally grinds to a halt as it attempts to tally file counts greater than 500,000 (at least on our system systems).
So what’s the solution? For many years we have been performing backups at the file level. Performing backups at the file level adds latency and can be very time consuming. The new technology is CDP (Continuous Data Protection). This technology, in fact, is not very new at all. Faster Internet connections enable us to perform backups at the sector-level over the wire. Sector-level backups are so much faster because only the changed sectors are transmitted.
R1Soft has pioneered this technology in the Linux market. Their kernel device driver (the heart of their backup agent) actually tracks block-level changes in real time. The next time the backup kicks off the agent knows exactly what blocks have changed. You might be thinking to yourself "That has to add overhead!" but, in reality, it uses no more than 10MB of physical RAM per 100GB the device driver monitors.
Image level backups are so fast we can back up our web servers in less than 5 minutes every 2 hours. These backups are less CPU and disk intensive than any file-level backup can offer.
To test drive image-level backups with R1Soft technology, visit WebHostBackups.com for more information.