A review of PHD Virtual for Citrix XenServer

Backup is an essential component of any IT infrastructure and there are dozens of products on the market that provide backup, archive, e-discovery, deduplication, etc features for the vSphere and Windows OS market. However when it comes to Citrix XenServer there is a rather small following of backup software providers that integrate with their hypervisor.  PHD Virtual Backup for XenServer is one of them.

Citrix XenServer has the option to use Hardware HBA, NFS, LVM over iSCSI/Fibre Channel, and Storagelink as virtual disk storage.  For those that are using LVM over iSCSI or Storagelink you will quickly realize that there is no easy way to get at the virtual hard disk files that make up your virtual machine.  If you are using NFS as your storage subsystem you will see .vhd files representing the virtual hard disks of your virtual machines…however, from my experience few are using NFS as virtual disk storage.

If you come from a Hyper-v or vSphere background this may seem a little odd at first as there isn’t a way unless you are using NFS to “copy” your virtual hard disk should you need access to it.  There is no “file” that makes up your virtual machine’s hard disk.  Instead using LVM the hypervisor is mapping the blocks on the shared LUN to the virtual machine…the hypervisor owns the file table mapping, for lack of a better term. Additionally in the event that you need to bring up your XenServer VM’s that are using LVM over iSCSI/FC or Storagelink it is required that you are doing a backup of the virtual machine metadata.  This metadata is in fact required if you intend to recover your virtual machines on a new XenServer host or during a DR event…without it you are left with a bunch of one’s and zero’s on a LUN and no way to make sense of it. For example, if you were to take a LUN that is being used by XenServer host A using LVM over iSCSI and were to mount that LUN to XenServer host B, without the metadata backup from host A that data is unusable. This compares to Hyper-v or vSphere which put a file system on the LUN and mounting that same LUN to another host is still readable, albeit you might have a few steps to bring it online.

Getting started with the PHD Virtual for XenServer installation:

Download the zip file from PHD Virtual, extract the files. Inside you will find documentation, the virtual appliance, and a client application.  Import the xva appliance into XenServer.  From the console grap the ip address and connect using http://%ipaddress%

From there you can download the PHDVB console or you can install it from the extracted zip file.  Once installed on first launch you will be asked for the hypervisor type, host name, user name, and password. Alternatively you can also launch the PHD Virtual Backup console by right clicking within the XenCenter management console.

From the console the first task is to configure a connection to the hypervisor followed by configuring a storage location for backups.  PHD Virtual supports an attached virtual disk to the appliance, NFS, or CIFS.  For my environment I chose a CIFS file share.

After that the only step left is to setup a job.  A job can be either a backup, restore, or replicate job.  The first two are pretty self-explanatory, the last one, replicate job allows you to setup a replication schedule for specific virtual machines on a specific schedule.  This replication job requires that you first setup a replication location under the configuration. Alternatively you can also setup backup, restore, or replicate jobs by selecting a virtual machine and right clicking on it. If you are using this functionality after selecting a virtual machine that context is brought in to the wizard. For example, if you select a virtual machine, right click and choose – PHD Virtual Backup – Backup the wizard will launch with the selected virtual machine as part of the backup job.

Backup retention is global for the appliance (which in large environments could be a potential area of concern) and allows you to configure the number of recent backups to keep as well as the most recent backup from each of the last (days, weeks, months, years).  This allows you to configure the typical (or custom) schedule that most want, however keep in mind it is global, it doesn’t have any ability to do granular retention for different sets of virtual machines. You do have the ability to create archive backup jobs or manually archive backups to make sure they are never deleted by the retention policy.

What PHD Virtual does do:

  • Very easy to install, configure, and learn how to use…In fact if you haven’t figured it out in a couple hours you should probably go find a new career.
  • Backs up XenServer virtual machines to a CIFS, NFS, or attached disk
  • Replicates virtual machines to/from another host or another PHD Virtual Backup appliance at another site
  • Makes the backups you do available via a CIFS share on the PHD Virtual appliance, what you will see is both the virtual hard disks for your virtual machines as well as an OVF xml file for easy import or transport.  
  • PHD Virtual Backup can export backups as an OVF, therefore making it easier to begin recovery as PHD Virtual Backup isn’t needed.

What PHD Virtual doesn’t do:

  • Does not have a backup solution for non-virtual (physical) servers.
  • No built-in replicate to the “cloud” options

Verdict:

  • If you are looking for a simple to install, configure, and use backup solution for Citrix XenServer PHD Virtual Backup has that covered  If you are looking for out-of-the-box deep application integration with Microsoft applications you’ll need to use Digiscope to extend the iSCSI mounting of virtual disks that PHD Virtual Backup uses as their recovery method when you don’t want to restore the entire virtual disk or virtual machine.

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