Server Virtualization has become a norm these days and this is evident from the increased emergence of virtual backup appliances in the storage market. Traditionally speaking, virtual environments enable the creation of software servers by allowing multiple operating systems to reside on physical machines and run their own applications. In the same way, a virtual backup appliance offers an OS and backup product in a ready to use package in a virtual server environment.
Therefore, virtual backup appliances are easy to deploy and scalable and can offer performance advantages over a backup application working on a physical server.
Technically speaking, a virtual appliance refers to the packaging of an operating system image and application (in this case backup) for deployment on a virtualized platform such as VMware, Microsoft Hyper V or Citrix XenServer. Therefore, virtual backup appliances are designed to be deployed with minimal configuration, which usually consists of scripted responses devised by the vendor and offered on power-up of the appliance in a virtual guest.
Nowadays, appliances are being offered by vendors in a pre-built way that includes all the required components of an application at a specific supported level of configuration. Thus, just a minimal work is required to make an appliance operational after boot-up as the user has to go with “power up, configure and go” approach in contrast with a standard deployment, where an operating system is built and patched to local standards before the backup application is deployed.
A virtual backup appliance deployment is therefore quicker and easier than building and deploying a backup application from scratch.
Now coming to the benefits of virtual backup appliances
- Optimization- Firstly, the operating system can be optimized in such a way that it gets automatically deployed with only the components required to run the backup software. This has the benefit of reducing complexity and dependencies in the deployment and reducing use of system resources. The vendor can also have the privilege of locking down unnecessary features, a task that the server or storage administrator would otherwise have to do.
- Network Performance- Within a virtual infrastructure, networking is implemented as either a virtual VLAN (vSwitch in VMware) or virtual network (Hyper-V), which can exist within one or multiple hypervisors. If communications within the virtual network doesn’t leave a single hypervisor on a single physical machine, users will benefit from reduced latency, which translates directly into higher throughput of backup data. Backup security can be improved by creating a virtual network purely for backup and keeping it within the hypervisor
- Scalability- Virtual backup appliances can be built into the deployment model of virtual environments and this move allows backup infrastructure to scale to meet virtual server requirements.
- Speed- When compared to the deployment of traditional backup infrastructure, virtual backup appliance deployment can be speedy, benefitting from being virtually deployed and preconfigured.
- Integration- Some virtual backup appliances integrate directly into the VMware ESX console, providing consolidated management of a virtual environment. This is particularly useful for the restore process, where data can more easily be restored back to a target guest.
- Compatibility- As most virtual backup appliances use existing backup products, it cuts down the training time for staff as they are already familiar with those tools. Additionally, features such as a backup replication can be achieved between physical and virtual deployment.
When it comes to disadvantages of virtual backup appliances, there are some trade-offs as well.
- Performance- In large database environments, a backup performance can turn crucial. But a backup application deployed on dedicated hardware will perform better than a virtual backup appliance.
- Device support- Virtual environments may not directly support tape, offering only disk-to-disk backups. This may represent a problem for moving data off-site.
- Upgrade/Support- All virtual appliances need upgrades and maintenance from time to time. This means applying patches as required and upgrading the underlying operating system and backup software is very much needed. This process could be an issue if the appliance is built on a platform for which there are no in-house skills. As a result, the only way to break out from here is to go for a new appliance running a latter code. However, moving data between backup servers and certainly between different versions of the application will be tedious.
- Sprawl- Having many backup appliances in large environments can require additional management overhead and this can turn into a serious issue.
Finally, virtual backup appliances are a good choice. But as every technology have its pros and cons; be careful of issues surrounding performance and ongoing manageability of these appliances as in the long run they may outweigh the benefits initially provided by going down the virtual backup appliance route.