One of the advantages of a virtual infrastructure is the ability to cost effectively replicate your production systems to a secondary disaster recovery environment. Not only can you do this with virtual machines, but there are now several options available to allow physical servers to be replicated to a stand-by VM. This post will briefly cover several products and solutions and provide multiple commercial options and a free alternative.
One of the engineers from our storage team asked me to join a discussion about whether or not restoring VMs from images made by any of the live VM backup utilities would be a reliable process for a client. I unknowingly joined what was really a battle about whether the client would be better off using SAN based snapshots, host based replication, or live VM imaging specifically for Exchange and SQL VMs. All are proven solutions, and depending on budget, recovery objectives, and service level agreements all solutions could be deployed with confidence. The customer, and this post, is focused on the live VM backup solutions and their reliability for Exchange and SQL. Based on cost of implementation and infrastructure required the VM backup tools are the most affordable and easiest to deploy, but they also leave you with the most uncertainty.
Before continuing I want to point out that normal backup agents still need to be used for Exchange and SQL VMs. Not one of the VM backup solutions can perform application maintenance or specialized backups, like the Exchange Information Store backup for example. Understand that the live VM backup tools only specialize in capturing a quiescent, working image of the VM operating system and application.
First let’s understand what we mean when we say quiescent data. In the latest VMware Virtual Machine Backup Guide quiescing is defined as:
Looking for a comparison of VM backup solutions? PHD Technologies, makers of esXpress, have put together a matrix of features comparing how their product stacks up to VMware’s VCB, Vizioncore’s vRanger, and even vRanger integrated with VCB.
Check it out online in original form here.
I have saved the matrix as a stand alone page as well.
updated 12-11-07 *****
After reading comments from readers I realized
I recently installed the latest version of Vizioncore’s vRangerPro and ran into an issue where 2 of the VMs would not complete a backup. All of the other VMs would complete without issue. Both backup jobs would stall at the “Acquiring VM Lock. This may take many minutes!” message in the job console window. I had to manually cancel the first stalled job (using CTRL + C) before the second job would begin and eventually stall in the same spot.
I was using vRanger installed with VCB 1.0.3 on the same server. The backup was going to a local NTFS drive. The job was configured with VCB integration.
I was able to get the jobs to work by
