Monday, 5 December 2011

Veeam Vs. vRanger Part 2: Similarities

As discussed briefly in my previous blog post comparing Traditional and VMWare specific Backup applications, Veeam and vRanger have both been built from the ground up specifically to backup Virtual environments, and hence have some fundamental similarities. Before I get into discussing the differentiators between the two products in detail, I thought it would be worthwhile providing a quick overview of some of the key similarities…

Both Veeam and vRanger leverage the vStorage APIs for Data Protection (VADP’s) which allow them to backup VMs across multiple vSphere hosts, without requiring the installation of agents either in the ESX servers or the vSphere hosts. When compared with traditional backup software approach of installing agent on each Server or Virtual server to be protected, this approach substantially reduces the complexity of installation as you don’t need to spend time installing agents in each VM to be protected. Additionally, ongoing management of your backup solution is easier; product updates can be applied centrally, and both products allow you to backup either individual VMs, or by vSphere host, so if you add a new VM to a protected host, it will automatically be included in the backup job.

Another major benefit of this approach is that the VADPs allow Veeam / vRanger to perform backups from a separate backup server or VM without placing a load on vSphere hosts. By utilising the snapshot capabilities of VMware vStorage VMFS backup snapshots can be performed without any disruption to the VM’s, or applications that run on them, effectively eliminating the traditional backup window. In contrast, using an agent based or guest level approach to backing up VM’s can lead to significant resource issues on the host, especially if backup jobs are scheduled to run simultaneously. Staggering backup jobs can offset this effect, but will increase backup windows.

Veeam and vRangers integration with the VADPs also allow them to take advantage of Change Block Tracking (CBT) to increase the speed and efficiency of incremental and differential backups. The CBT feature creates a ctl.vmdk file for each VM containing a map of the virtual disk, that indicates the timestamp and last modification for each zone of the disk since the last snapshot was taken. Veeam and vRanger can access this information, and only need to process the blocks of the VM disk file that have been modified since the last full, incremental or differential backup was taken.

Currently, Veeam and vRanger also share some common weaknesses; they are both only capable of backing up Virtual Machines, so if you have any physical servers you will need a separate application to protect them, and there is no tape support in either product, so if you need to backup to tape, you will need a second solution to push the backups generated by Veeam / vRanger to tape. In addition to this, for applications that are not VSS aware, backing up at the host level can cause problems as the applications don’t know they have been backed up, so won’t truncate logs etc. It’s worth noting that both companies have plans to address some of these issues, I will discuss this in more detail in a later post discussing development roadmaps.

In summary both Veeam and vRanger have similar fundamentals, both can offer some substantial advantages and have some drawbacks when compared with traditional agent based backup software. Once you move past these fundamentals however, there are some fairly substantial differences between the products. In my next post I will compare both products approaches to data reduction, and the methods they employ to minimize the amount of storage required to hold backup data.

Next Up: Veeam Vs. vRanger Part 3: Data reduction techniques

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