Since the beginning of backup times (almost), backing up specific platforms has typically required an agent optimized for the environment in question. Typically, you’d get one agent installed on each server, the agent would interact with the backup engine/server and do its thing. This became very cumbersome when virtualization exploded, when adding a server (virtual) could be easily done with one phone call to your favorite admin. Not just one, but dozens or hundreds. It meant installing one agent on each virtual machine, which quickly became cumbersome and operationally created data protection gaps and issues.
Along came agentless backup which significantly reduced the difficulty associated with backing up virtual machines. With this approach, you can capture all of the VMs with a proxy server without having to install an agent in each virtual machine. Less administration, less data loss exposure…what else could be better? It certainly made agent backup look old and clunky.
Not so fast…. As is often the case, there’s more than meets the eye. You can’t just go 100% agentless…Here’s why:
- With VMware, any virtual machine that does not use native VMFS cannot be properly protected “agentless-ly” leveraging the native VMware API’s. Raw Device Maps (RDM’S), and SQL Cluster disks are both examples where a different File System to VMFS is used.
- Our competitor Company V’s agentless technology, for example, can’t protect these systems. In contrast, Arcserve easily can through the installation of an agent. In a recent conversation with our field, we confirmed that we often see customers who use RDM’s being told by Company V that they have to convert them to ‘normal’ virtual machines. That’s a dirty little secret, and something that many customers just won’t deal with. (By the way, this company’s recent announcement around agent deserves serious inspection – a glorified desktop agent is not the same thing as a full-featured server agent.)
To quote one of our field leads: “Our physical server support through the UDP agent install is a significant advantage over Virtual only agentless solutions. The ability to be able to protect and recover physical machines as bare metal, as virtual machines or at an object and file level is obvious, but it also allows us to protect virtual machines that are not supported by the native tools and API’s. There are also circumstances where it may be preferable to install an agent inside the virtual machine – for example if the virtual machine is very large or has a very high change rate, or if the VM Tools are perhaps not properly configured or up to date.”
Also, with our High Availability module, which provides Continuous Data Protection, Fail Over, Fail Back and more, supporting replication and backup of an MSCS cluster running on Windows 2008 R2 in VMware with physical RDM is easy. It is however a big issue with our competitors Company V and Company Z. In addition, remember that Arcserve offers great deduplication, global across nodes. Not everyone does that!
Beware of 100% agentless solutions – they just don’t cut it in many cases!