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Backing up Hyper-V guests with Dedup

Level 2

Here is my problem with my current setup (which consists of a Dedicated Server running BE 2015 with 5TB storage, and a 3600 Appliance with 5TB storage)

We use deduplication storage on both systems, and we copy jobs from one unit to the other for offsite backup storage.

We are mainly backing up Windows Server 2012R2 systems, and the majority of them are virtual machines.

Veritas recommends that we backup the guest VM’s directly from the host. The main reason for doing this is that you get single instance restore (you only have to restore the vhdx files), and because you cannot perform a restore to virtual for Server2012 R2 systems, so by backing up the VHD you get a similar experience.

The main, really huge, problem with this is that it chews through storage at a rapid pace, even with deduplication. For example if I have two servers configured almost identically, the only difference being the application I am running on them, the VHDX file will be drastically different, and BE will not perform deduplication even though 90% of the contents of the VHDX are similar.

What we have done in the past to prevent this is to back each server up from the guest, so it is treating all my servers as physical servers. The only problem with this is that I am not backing up the vhdx so recovery takes longer as we have to build a VM, then perform a simplified disaster recovery of the server, instead of just restoring a vhdx file. The Huge, upside to this method is the amount of storage space consumed during routine backups., as dedup is able to compare all the files on a server.

As an example, we had been backing up our servers treating each one as a physical server for over a year without any storage problems using only 2.5TB of space with a 6month retention period.

Since we moved to BE 2015 Veritas tech support strongly pushed us to back up from the host. We made this change, believing that maybe things were fixed with dedup and vhdx files. In a matter of three weeks we have consumed 4.6TB of space.

I am looking for some clear direction from Veritas on the capabilities of deduplication and virtual machines, as this may push us to consider moving to something like Unitrends in the next round of maintenance renewals, which can dedup vhdx files.



Employee Accredited Certified

When you backup using the agent the dedupe is done using the file level stream handlers. With VHDX the equations changes and it uses HyperV stream handlers and since the file type that you are backing up changes so does the dedupe ratio that you get. I would say it is not a good comparison but whichever suits your environment. Since you have space limitations go for agent based backup. In case you install BE 15 on another physical server and have much larger dedupe folder then you can use Hyper V based virtual machine level backup.

Level 2

Come on, give purchasers of your product a fair and clear statement about BE 2015:

both of these hold true:

  1. Backup hyperv guests from host at the cost of storage space even with the deduplication option
  2. Backup Hyper V guests with agent based (treat as a physical server) and lose recovery ease - as you can't do convert to virtual due to Secure boot, and you cannot recover just the VHDX as your not backing it up. You are left with longer recovery cycles as you have to build a VM first and then do a Simplified DR. All this to save space during intial backup.