With the release of hyper-v 2012R2 the backup process of the system was changed. Now for some reason there is very little documentation on this.
The new process involves the use of checkpoints
instaed aswell of as VSS to backup the VM (VHDX).
After some futher investigation and with the help of Veeam, many thans to Anton Gostev & Alexander Fogelson for there help, There are a few clear ups worth mentioning.
- Both host and in-guest VSS are also used as previously.
- VM on the volume snapshot is always in its consistent state as volume snapshot is created after the VM freeze.
- Checkpoint is indeed crash-consistent, but is untouched by the backup process.
- Checkpoint is needed because different VMs on the volume will require different time to complete guest VSS freeze.
- This also improves support for non Microsoft systems that don’t have in guest VSS.
Originally when backing up Hyper-V VM’s a VSS snapshot would be created, mounted, and that VSS snapshot would be backed up. similar to how we backup (or used to before we started backing up VM’s) Exchange, SQl AD…
The new way basically involves taking a checkpoint (formally known as a snapshot) of the VM, the checkpoint freezes the VHDX file and performs all new writes to a temporary AVHDx file. Thus while the checkpoint is active the original VHDX files can be backed up.
The one thing to take note of is that a checkpoint is crash consistent and not clean. Now these days this is not a big deal as almost all modern databases will load and cleanup there own databases after a crash consistent restore. Also 3rd party backup solutions such as Veea will still directly quis the VM’s and perform VSS snapshots natively within the VM to guarantee clean backups.
Although being crash consistent we do get an easier backup process and using hardware based backups should be easier as we no longer require a hardware VSS provider.
Windows based VM’s will be backup consistent and not crash consistent.
In part I we talked about the concepts and fundamentals of backing up a Hyper-V environment.
In Part II we’re going to talk about Different software that can be used to achieve this.
Now obviously there are multiple vendors offering backup applications, I cant go over them and I’m going to stick with the two that I personally work with.
I will however mention that most traditional backup software has now evolved to support backing up of Hyper-V, however they seem to support less options and be less flexible as they try to back up hyper-V using the same guidelines that they’ve used for years for traditional backup and most of the time these guidelines just don’t fit. Another thing worth mentioning is that you can actually use windows 2012 built-in backup to back up Hyper-V. It does a reasonable job and is free. however it is of course limited and I wouldn’t use it in a clustered environment.
Now the two programs I’m going to focus on are:
- Microsoft System Center DPM (Data Protection Manager)
- Veeam Backup & Replication
Both these programs follow the guidelines that I outlined in my previous post regarding VSS and both have a degree of visibility into the VM including item level recovery of objects from with in the VM.
Lets start with DPM.
DPM is part of the System center package so if you have purchased System Center then you have DPM. Therefor anyone using SCVMM is also entitled to use DPM. DPM supports backing up of any Microsoft VSS Product with specific support for Hyper-V, Exchange, SQL & Sharepoint.
The first thing to note about DPM is that it supports backing up to tape or to DAS (or any other form of local disk like iscsi or fiber), backing up to a nas is not supported. In the upcoming 2012R2 version you will also be able to back up to Azure and VHD storage pool disks.
When you run your initial Hyper-V backup a full backup will be performed know as a “replica”. After the full backup is created all future backups will be incremental know as “express backups” This meeans that after your initial backup all backups are incremental and take a short time to run, this in turn allows you to run multiple backups during the day and not just a single backup during night hours. Now that you have a backup or backups of your VM’s you can of course perform restores. With DPM we have two restore options for VM’s. The first is a full restore of the VM. This is basically used if your VM was accidentally deleted or harmed so badly that you just want to restore a previous copy of it. The second option is file level restore. In this case DPM will show you the actual files from within the VM (provided that the VM is a windows based VM) and allow you the option to restore specific files from with in the VM.
Now although I said that DPM supports Exchange, Sharepoint and SQL you can not perform Application level restores of these services from a VM backup. So your basically going to have run a second backup that is not Hyper-V based (this will require an agent in the windows server VM) to backup your Exchange & SQL Databases.
- Part Of the System Center Package
- Once full forever incremental Backups
- Support for all VSS aware applications
- Application layer protection requires a separate backup
- Limited choices for backup destination
In this post we’ve covered Microsoft System Center DPM in a Hyper-V environment. In part III I”ll explain the benefits of using Veeam Backup & Replication to protect your Hyper-V enviroment.
Great news! The new and highly anticipated version of Veeam Backup & Replication has just been released.
For those of you aren’t familiar, Veeam Backup & Replication is one of the leading backup applications for backing up, replicating and restoring Hyper-V.
I’ll be writing a full post next week regarding backing up of Hyper-V using Veeam.
For now some of the new features available in Veeam 7 Are:
- Support for tape device as backup target
- Support for Exchange 2013 and Sharepoint 2013 (Object level restore)
- 1 Click Restore
- Virtual Lab for replicas – Allows the use of existing replicas to set up a virtual lab or test environment
- Wan Acceleration for fast backups over WAN
- Backup From Storage Snapshots – Allows the use of storage snapshots for customers with HP P4000 or 3par Storages
- VM backup copy and archive – You can now choose specific VM’s to be copied out of a backup job and apply long-term retention policies to that particular VM
Some Other Cool Features (already in place from previous versions are:
- Forever incremental Backups – After one full backup all future backups are incremental
- Instant Recovery (Allows almost instant availability of a failed VM, The VM is run directly from Backup without the need to perform a full restore
- File recovery from both Windows & Linux VM’s
- Compressing and dedupe of backups
- VM replication with multiple point in time restore points
- Full VSS compatibility for consistent backups in Microsoft environments.
Stay tuned for my future post on using Veeam Backup & Replication.