Protection of VMware virtual machines (VMs) is becoming a key part of the day-to-day job responsibilities for a growing number of backup administrators. As this task takes on more importance, verifying how backup software protects specific VMware file types, such as vmdk, vmx, and vmsd, becomes critical since it impacts how well companies can protect and recover these files.
This topic was brought into focus by a reader response to a recent blog entry about how Asigra Televaulting eliminates the need for backup agents on each VMware VM. What this reader wanted to know was:
- How does Televaulting handle the different VMware-specific file types?
- Will alternative storage solutions fit with these related file types?
To answer this reader’s questions, I checked with Asigra’s technical support to get a deeper understanding of what the differences are between these VMware-specific files and how, or if, Televauting manages them.
For all practical purposes, Televaulting treats these different files as one common entity and not as separate files. The vmx file is a configuration file associated with each VM while the vmsd file stores metadata associated with VM snapshots. By themselves, they are quite useless since the core VM data is stored in the vmdk file associated with each VM. The vmdk file contains hard disk images and represents over 99% of the useable data found in these different types of VMware files that are associated with each VM.
The level of recovery that Televaulting provides for individual VMs hinges on how administrators configure Televaulting’s DS-Client to back them up. Televaulting offers two agentless backup options from which administrators can choose: a full VM backup and a guest VM backup.
Using the full VM backup, there are no choices of file type when doing recoveries; the Televaulting DS-Client backs up and manages the VM as a full image so companies can only recover the entire VM image. When doing these backups, the Televaulting DS-Client only backs up the VMware-specific files associated with a specific VM.
Conversely a guest VM backup acts like a normal backup and treats the VM as it does any other server that is not virtualized. Therefore it has all of the normal backup and recovery options such as application awareness and the ability to perform selective backups of specific databases, emails and file systems.
The backup options that Televaulting offers for VMware compare favorably to other backup software products that may use the VMware snapshot option that is natively found in VMware. The VMware snapshot option creates a point-in-time snapshot of all of the VMs hosted by the VMware ESX server so all VMs are protected at the same time and the only recovery option is to recover all of the VMs back to that same point.
Using Televaulting, administrators have more granular control of what sort of backups they create and what level of detail they capture. Using the full backup option, administrators can recover all of the data on a specific VM as opposed to the entire server. Using Televaulting’s guest VM backup, companies can restore the application data, email message or file on a specific VM and, when they select Televaulting’s continuous data protection (CDP) feature, companies can also restore this data to a specific point in time.