In this second of a two part series, we’ll discuss available options for XenServer Backup.
In Part I of this blog post , I began discussing backup options for XenServer. I touched on the tools that come with XenServer and cruelly ended it without getting into the topic of third party backups. In this second part, I am going to completely skip over that subject and make you wait for Part IV. Don’t ask what happened to Part III. OK, I am done kidding around (for now). Third party backup solutions generally fall into one of three categories: backups done through storage replication, backups performed at an OS level, and backups performed using snapshots through the XenAPI.
Backups done through storage replication utilize the replication abilities built into your backend storage (SAN or NAS). The VMs stored on your SAN or NAS get replicated to another site by the storage device. This is both a backup and disaster recovery option. However, it is probably the most expensive option because it requires two or more storage devices in different geographical locations with a pipe between them big enough to support the replication traffic. File level restoration becomes a problem because the VM as a whole is replicated without a way to parse data inside the VM.
Backups done utilizing at the OS level is the traditional method of backing up a server. Even though these are virtual machines, they are still fully functional servers. The hardware they run on is different, but in essence to the OS, that is a difference in drivers used. The OS is still the same. You can use your traditional backup software which usually (not always) places an agent in the OS to perform backups of the server system state, data, and files. This could be solutions from Symantec, Carbonite, Acronis, ComVault, and hundreds of other backup vendors. For those of you with smaller Windows server VMs and wanting to save money, you can even employ Windows Backup which comes with Windows. OS level backups is a method in which you can keep from using multiple solutions providers and will provide the most granular level restore options for the OS, applications, and services. One solution will probably handle it all. However, you will be restoring a server the same way you would a physical server. Fix the hardware, install the OS, install the backup agents as needed, and then restore. This is a big differentiation from solutions geared towards backing up virtual machines as a whole image because they enable you to restore a VM back to its state at the time of backup without rebuilding the server.
Snapshots with XenAPI
Backups done through snapshots utilizing the XenAPI is a very common form of backup for a XenServer. This method backs up the server as a whole image. Many solutions utilize this method. In fact, you can find free premade scripts people have posted that will perform this function for you. You just won’t get any bells and whistles with a script. And that is what differentiates the 3rd party backup solutions over just getting a script. The bells and whistles 3rd party vendors include catalog and sort options, give broader control over the storage being used, and other features. Some of these solutions have features that will mount the snapshot to allow you to perform granular recovery. PHD Virtual (acquired by Unitrends last year) was one of the first well rounded support offerings for XenServer. Over the last few years, it has grown to allow you to do granular level restores even for Exchange and SharePoint. Quadric Alike is a well-rounded solution. Its product trial is a free version for one XenServer that does not expire. So, if you are a small shop with only one XenServer, here is a good free solution.
Ideally, a solution that provides both physical and virtual server backup solutions with granular level restore would be what a lot of administrators are looking for. It would be your single backup product that covers both physical and virtual worlds. SEP Software Corp offers such a solution as well as Symantec NetBackup. Many of these solutions started out as a standalone products which were incorporated into a package or integrated into another solution.
As I stated, I am not covering anything in-depth and my purpose was not to review solutions in this article. It is more about awareness. If you would like to offer a suggestion I did not mention, please do so in the comments below.
Craig R. Kalty (CCIA, CCEE, CCA, MCITP:EA, MCITP:SA, VCP)
Sr. Network Consultant
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