Backup is the activity of copying files or databases to a disk or tape so that these may be used to restore the original after a data loss. It is always advised to keep one backup in a different location from the others.
Why do you need a backup ?
Data is one of the most important aspects of our computer systems and the probability of a failure is lower these days due to upcoming technologies. A data loss can occur due to hardware failure, software bugs and natural calamity so being a smart user, one should go for data backup which is cheap, fast and a prevalent way of saving data. And since backups can be stored in
different locations from the original data, it is safe from a any natural calamities.
What is CDP?
Continuous Data Protection or rather a CDP Server is a server software application enabled in servers running Windows and Linux operating systems for disk-based data protection and disaster recovery.The idea behind CDP was to change the approach to backup solution which was a switch from tape-based system to hd-based system that is less complex and less expensive, with the opportunity to handle better backup images.
The disk-based storage protects the disk volume data by syncronising point-in-time snapshots (a read-only copy of the data set frozen at a point in time and allow applications to continue writing to their data. This is mainly performed in high-availability systems where downtime is not acceptable) over the network. Instead of scheduling periodic backups, the system immediately logs every change on the host system.
Now , a point-in-time snapshot of the disk is created by a Linux command line utility Hot Copy (hcp), without interrupting applications on the Linux servers, while the system is running. If any block level changes are made to the device, Hot Copy makes a backup copy of the changed blocks only.
Rsync backups
Rsync over SSH ,which ensures all data transferred has the benefit of being secure, is an ideal method for incremental backup of large number of files. In this process, it copies only the files, preserving file permissions, links and other data, that has been changed since the last backup or sync was made which saves time and bandwidth. This makes restoration of data very onto a
new server very simple.
How to Restore Data?
At a particular point-in-time, the recovery point stored on the CDP server is virtually a disk image and each disk image has the file system format, partition table and volume management data required to rebuild the entire disk. You need to boot the server into a special disaster recovery mode incase of disaster or quick roll-back of Linux/Windows servers. Once its booted into the recovery mode, you can stream a recovery point directly onto your server hard disk from the CDP server over any TCP/IP network.
Advantages of CDP
* Near-Continuous Backups, providing hundreds of recovery points per day scheduled as little as 5 or 10 minutes apart
* It is Resource-friendly and the processor usage and bandwidth utilization during backups are low.
* It has the ability to visualize, create, and verify backups taken.
* Data is protected as the backups that are being processed are fully encrypted.
