Best Practices forHyper-V Backups

Greg Shields, MVPSenior PartnerConcentrated Technology

www.ConcentratedTech.com

@ConcentratdGreg

About the speaker

Over 15 years of Windows experience.● Administrator – Managed environments ranging from a few dozen to

many thousands of users…● Consultant – Hands-on and Strategic…● Speaker – TechMentor, Tech Ed, Windows Connections, MMS,

VMworld, ISACA, others…● Analyst/Author – Fourteen books and counting…● Columnist – TechNet Magazine, Redmond Magazine,

Windows IT Pro Magazine, TechTarget Online, others…● All-around good guy…

Honesty Moment: This Isn’t Fun.

Hyper-V backups are not as trivial as they might seem.● Hyper-V host requires backup● Virtual machines require backup● Files inside VMs require backup● System State requires backup

Bad decisions mean Hyper-V backups might not back up with the granularity you might need.● “I need to grab a file off a VM.”● “I need to restore a SQL database or a database row in a VM.”● “I need to recover an individual email from Exchange.”● “I need to bring back a VM from a specific point in time.”

Your Steps in Constructing the Right Solution

1. Determine what you want to backup.● Files and folders?● Applications?● Entire virtual machines?

2. Determine from where you want to backup.● Virtualization introduces “perspective” with backups.

3. Determine how you want to backup.● Understanding backups means understanding VSS.

4. Determine with what will you backup.● Native tools?● Third-party solutions?

Step 1: What do you want to backup?

Virtualization adds to the number of objects that could potentially be backed up.● Files● Folders● Application objects● Applications● Operating systems● Virtual machines● Virtual host● Virtual cluster

Operating System

Applications

Files and Folders

Hypervisor

Virtual Host

Storage

Hyper-V is Unique: The vSphere Architecture

Hyper-V is Unique: The Hyper-V Architecture

Step 2: From Where do you want to backup?“Perspectives”

Perspective Drives Backup Agent Location

Agent in thePrimary Partition

Perspective Drives Backup Agent Location

Agent inside theVirtual Machine

Perspective Drives Backup Agent Location

Agent within theStorage Layer

Perspective Drives Backup Agent Location

Cluster Aware Agent

Some Perspectives Can’t Deliver

Greater granularity with some perspectives. Less granularity with others.

Less backup/restore effort with some perspectives. More backup/restore effort with others.

Some perspectives can’t deliver onwhat you want to backup.

Step 3: How do you want to backup?

Backing up just files and folders is easy.

Everything else requires the assistance of the Microsoft Volume Shadow Copy Service, VSS.● Originally used to create volume snapshots for user self-service

restores. Remember the “Previous Versions” client?● Now a major component of all application-aware backups.

VSS Enables the How

VSS is a Windows service that interacts with installed applications…● …to inform applications that a backup is about to occur.● …to report when the backup is complete.● …to instruct applications to perform post-backup tasks such as truncating

logs and cleanup activities.

The first job of VSS is quiescence.● Quiescence = “quieting”.● Coordinates backup jobs with applications to ensure successful backups

without data corruption.

The second job of VSS is coordination.● Between applications, their data, and backup activities.● Between backups and storage.

VSS Enables the How

VSS is used when transactional-based applications installed to Windows servers require backups.● Exchange, SQL, AD, Oracle, others…

Virtual machines are a kind of transactional-based application.● Virtual machines require quiescence for proper backup.● Think of VHD files like little transactional databases.● If anything changes in that database while you’re backing it up, you’ll

end up with corruption.● Things are constantly changing in VDK files!

VSS’ Three Components, Single Server

Volume Shadow Copy Service

VSS RequestorVSS Writer

VSS Provider

Disk Volume

Backup ApplicationMicrosoft Exchange

SQL ServerOracle

Active DirectoryOthers...

Operating SystemStorage Array

VSS’ Three Components, Hyper-V

Volume Shadow Copy Service

VSS RequestorVSS Writer

VSS Provider

Disk Volume

Windows Server Backup

Hyper-V Writer

Operating SystemStorage Array

VSS Writer

Virtual Machine

Microsoft ExchangeEtc...

Disk Types Impact Backups

Hyper-V can support many different types of disks.Different types require different backup approaches.● Fixed-size VHDs● Dynamically expanding VHDs● Passthrough Disks● iSCSI Direct Disks

Step 4: With what do you want to backup?

Your options abound…● Windows Server Backup● Everything Else

Windows Server Backup, a Minimal Solution

Windows Server Backup is Microsoft’s native solution for backing up Windows Server 2008/R2 and Hyper-V.● Disk-to-disk backup solution.● Designed for small environments, limited uses.● Single-server focus.● Disk Volume focus.

● No direct restorability for VMs.● No direct restorability for files.● No direct restorability for application objects.

VM Backup via Windows Server Backup

Register the Hyper-V VSS Writer with WSB.● Click Start, click Run, type regedit, and then click OK. ● Locate the following registry key:

− HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion

● Right-click CurrentVersion, point to New, and then click Key. ● Type WindowsServerBackup, and then press ENTER. ● Right-click WindowsServerBackup, point to New, and then click Key. ● Type Application Support, and then press ENTER. ● Right-click Application Support, point to New, and then click Key. ● Type {66841CD4-6DED-4F4B-8F17-FD23F8DDC3DE}, and then press

ENTER. ● Right-click {66841CD4-6DED-4F4B-8F17-FD23F8DDC3DE}, point to New,

and then click String Value. ● Type Application Identifier, and then press ENTER. ● Right-click Application Identifier, and then click Modify. ● In the Value data box, type Hyper-V, and then click OK. ● On the File menu, click Exit.

VM Backup via Windows Server Backup

WSB’s Idiosyncrasies

WSB must back up all volumes hosting VM files.● If VM configuration files are on the D: volume…● …and the VHD files are on the E: volume…● …then you must back up both the D: and E: volumes.

WSB can either dedicate a drive to backups, or it will overwrite old data with each backup.

WSB cannot restore individual VMs. Cluster Shared Volumes cannot be backed up by WSB. VMs that contain two or more snapshots will not be

automatically restored.● Requires manual intervention.

VSS’ Idiosyncrasies

Disk types impact backups!● Passthrough disks cannot be backed up by the Hyper-V VSS writer.● iSCSI Direct LUNs cannot be backed up by the Hyper-V VSS writer. ● iSCSI LUNs attached to the primary partition can be backed up.● VMs that contain dynamic disks must be backed up offline.

Saved State backups will cause periods of downtime.● Saved State backups occur when VMs don’t meet VSS requirements.

− Missing Integration Services− Running OSs that lack VSS support

● Saved State downtime occurs during VSS snapshot creation.

Third Party Solutions, or,“What WSB Got Wrong”

Boy, they sure didn’t make it easy.

● Granular backup and restore.● Minutes of RTO, not “from yesterday”.● Changed block tracking● Deduplication, and compression.● Consolidation of perspectives.

− One solution for restoring files, folders, application objects,and virtual machines.

− One solution for backing up data, irrespective of disk type,connection, or location.

● Dead simplicity.

Best Practices forHyper-V Backups

Greg Shields, MVPSenior PartnerConcentrated Technology

www.ConcentratedTech.com

@ConcentratdGreg

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