Why Use Virtual Appliances for Backup in ESXi Environments?
After spending a lot of time under the hood of ESXi, we have concluded that traditional backup methods are going to need a tune-up in that environment. The fastest, most reliable and maintenance-free way to back up from ESX platforms is to put a backup run-time right on the ESX server to back up images to a storage device or network. However, a distributed architecture is advantageous for the ESXi platform, using virtual appliances (VAs) to share the backup load instead of concentrating it on a central ESXi server.
Remember that there is no service console in ESXi. That means backup solutions and architectures that were designed to run through the ESX service console will need to be adjusted. In ESXi, backups can execute in a central backup server, but scalability is a concern. Our tests and evaluation found backup performance slowed and risk increased once there were more than four ESXi hosts with about 30 VMs each.
Scalability and performance are why I advocate a distributed architecture using virtual appliances to back up in the ESXi environment. In a virtual appliance architecture, backup job processing and image transfer take place on the VAs, instead of on the ESX service console. This often leads to better performance. For example, in ESX environments the service console is limited to CPU 0 and 800 MB of RAM. By using VAs instead, you can get two or more virtual CPUs, which enables backups and recoveries to execute much faster. Virtual appliances are also advantageous for working with the vStorage API that is part of ESXi. If vStorage API is used without virtual appliances, uncompressed backup data is sent over the network for centralized processing. Distributed virtual appliances compress the backup data before sending it over the network for storage, so less bandwidth is needed.
While the VA architecture provides distributed processing, management remains centralized. The backup server gives administrators single-pane view of all backup activity, so adding VAs does not add to management complexity if it is done correctly in your backup product.
The VA architecture maintains the advantages of direct-to-target backup agent-free execution that administrators enjoy in the ESX environment, while adding scalability, speed and performance protection for the ESXi environment. The architecture transitions backup operations away from a potential single point of failure (the ESX server) to distributed processing, which reduces risk and enhances performance. Depending on your vendor, the VA architecture can also support replication, making it an outstanding platform for data protection in the ESXi environment.
Posted by Jason Mattox on 10/28/2010 at 12:49 PM