QualiSpace Blog

Continuous data protection (CDP) is a form of data replication that copies data from a source to a target. True CDP does this every time a change is made, while so-called near-CDP does this at pre-set time intervals. Near-CDP is effectively the same as snapshotting.
Because true CDP copies all delta changes, a system can be restored to any point in time required. This can be especially useful if you need to roll back to a point before a corruption event took place, for example.
Because they depend on fixed-interval copies, near-CDP/snapshots only allow you to roll back to a given point in time. For this reason, true CDP offers a recovery point objective (RPO) of zero, while the equivalent for near-CDP/snapshots is the last time a copy took place.
Continuous data protection can be implemented in two main forms: software based with agents running on designated servers, or as a hardware-based appliance that can be in-band (in the data path) or out-of-band (outside the data path).
How does CDP work?
Continuous data protection works by copying changed data from the source system to a target. Often, this will be disk at the same site as the source, and this provides a method of effecting very quick recovery of data.
However, it is possible to replicate off-site and this clearly provides much greater protection and potential disaster recovery provision. With some CDP products you can replicate to two locations — one on-site for rapid recovery and a disaster recovery site further afield.
True CDP systems record every write and copy them to the target where all changes are stored in a log. In case of a physical system failure, the continuous data protection system will have kept all changes up to the last write before failure, and you can restore to that point or to the last point before any corruption occurred.
True CDP systems will handle replication of files or applications with equal ease as they record every change.
By contrast, near-CDP/snapshot systems copy files in a straightforward manner but require applications to be quiesced and made ready for backup, either via the application’s backup mode or using, for example, Microsoft’s Volume Shadow Copy Services (VSS).
 

For the full month of April, our focus is on CDP as what is the biggest headache of any Business? We asked this question to a group of people. Most of them said Data Security. Aren’t they right in saying so? We all have to agree that Data Security is the critical aspect of any business. Imagine what will happen if the Finance Data is suddenly deleted? Without a proper backup solution, the situation would be out of control. So, what is the need of the hour? Obviously, it is a proper backup policy in place. Since Ages, businesses have been following traditional ways to back up the critical data. Even today many companies follow the age old Tape backup policy.

While the traditional method works in many cases, in most of the cases, it is not very feasible. If the backup was taken last night at 12 midnight and the system crashes today at 3:00 pm, the data written between the last backup and the time of crash will be lost permanently. This is certainly not a great way to maintain backups. Today’s businesses have to move towards advanced and sophisticated backup solutions than relying on the Traditional methods. So, what is the solution to ensure availability of data all the time? The solution is called CDP or Continuous Data Backup.

CDP is the most modern way of maintaining Data Backup. The name itself is self-explanatory. Unlike the Traditional methods, CDP ensures backup is created every time a file is modified or created. Moreover, it also allows keeping recovery points and archiving points which help to restore a previous version of the modified files. This also helps to even restore a good copy of the corrupt files. Since the backup is done at the granular or the block level, it also helps to backup files which are locked by processes running on the servers. Unlike Traditional Backups, restoration is easier as you don’t have to specify the point in time to which you would like to recover until you are ready to perform a restore. There are a few CDP systems which in a proper sense are not exactly CDP, but they can be called as Near CDP. The difference between a true CDP and a Near CDP system is that in case of True CDP, the backup is taken place every time a file is written or modified, while in case of Near CDP system, you have to schedule when the backup job will run. So, how it is even called a Near CDP system? Well, it can be called a Near CDP system because after the first full backup, it will back up only the new blocks of data written on the drives. Hence you can schedule the backup as near as every 15 minutes. One example of a Near CDP system is R1Soft CDP, one of the most widely used backup system in the Hosting Industry also provided by QualiSpace.

So, now we all know how important it is to have continuous backup and avoid headaches that may be caused due to lack of availability of proper backup whenever required. So, invest now in a good CDP Backup system which will save you a lot in future.