Modern Data ProtectionBuilt for Virtualization

Microsoft VSS: What Every VMware Admin Needs to KnowGreg ShieldsMicrosoft MVP and VMware vExpert

2

Microsoft VSS: What Every VMware Admin Needs to Know

When it comes to Microsoft VSS, there’s more to backing up virtual machines (VMs) than meets the eye – even in VMware vSphere environments.

Datacenters today place as much importance on application data as file data, especially data associated with high-priority applications like Microsoft SQL Server, Exchange, and Active Directory and Oracle. This prioritization means your backup solution must protect your applications just as well as it protects your files, folders and VMs.

Protecting applications in the Windows world, however, isn’t always an easy task. Applications need special treatment if the data you’re capturing is in active use and must later be restorable. Virtualized applications require special treatment as well, and you also need to be aware of how your data protection solution integrates with Microsoft’s onboard Volume Shadow Copy Service (VSS).

You read that right. Even VMware vSphere environments must respect Microsoft technology when it comes to application backups. Respecting how Microsoft VSS operates—and how your backup solution integrates with it—has become a mission-critical skill in modern data protection.

First, the VSS deep-dive…Microsoft’s VSS, is Windows’ built-in infrastructure for application backups. A native Windows service, VSS facilitates the creation of a consistent view of application data during the course of a backup. It relies on coordination between VSS Requestors, Writers and Providers to quiesce—or “quiet”—a disk volume so backups can be obtained without data corruption.

That’s the technical definition. In simpler terms, VSS alerts the installed applications that a backup is about to take place. It coordinates backup activities between the OS and running applications. And it alerts the OS after backups are complete, instructing applications to perform important post-backup tasks, such as truncating logs and other application-specific cleanup activities.

Notwithstanding your hypervisor, VSS participation is generally necessary for backing up running applications on Windows servers. Those applications can be Exchange, SQL Server, Active Directory, Oracle or any application that requires constant access to files on disk.

Recall that the primary job of VSS is to “quiet” applications just prior to a backup. This action creates a point in time from which backups are then sourced. That point in time guarantees that the server, the applications and the backup solution maintain a consistent view of data.

3

Microsoft VSS: What Every VMware Admin Needs to Know

Figure 1: VSS components

Maintaining this consistent view requires the coordination of three VSS components (Figure 1). At the upper-left are a set of VSS Writers. Each VSS-aware application installed on a server also installs its own VSS Writer. The VSS Writer coordinates backup activities with the installed application, for example, telling the application when backups are about to begin.

On the upper-right is the VSS Requestor. It coordinates VSS activities with your backup solution. The VSS Requestor requests a volume shadow copy be taken, which in turn triggers each VSS Writer to instruct its application to perform whatever actions are required to prepare for the volume shadow copy.

The third component is the VSS Provider, which creates and manages the volume shadow copies themselves. The VSS Provider can be either the operating system in combination with its file system or it can be a hardware provider on an external storage array.

VSS Writer VSS Requestor

Microsoft Exchange SQL Server

Oracle Active Directory

Others...

Backup Application

VSS Provider

Volume Shadow Copy Service

Disk Volume

Operating SystemStorage Array

VSS Writer VSS Requestor

Exchange Server Etc.

Your Backup Solution

VSS Provider

Volume Shadow Copy Service

Disk Volume

ESXi Host

Operating SystemStorage Array

Disk Volume

Virtual Machine

Note: You can use the command vssadmin list writers to list the VSS Writers that have been installed on a Windows computer.

4

Microsoft VSS: What Every VMware Admin Needs to Know

Now, integrating your backup solution…Although VSS has long been used for backing up running applications, it has become even more critical in virtual environments where entire VMs are backed up at once. This requires backing up a VM’s disk file as a point-in-time backup, a process that requires the same special treatment—and VSS quiescence—as applications.

In a sense, VMDK files are a lot like application databases in that a VM’s file system is always changing, and some mechanism to “quiet” the VM’s file system is needed for backups to maintain data consistency.

Figure 2: Integrating VSS with vSphere and your backup solution

VSS Writer VSS Requestor

Microsoft Exchange SQL Server

Oracle Active Directory

Others...

Backup Application

VSS Provider

Volume Shadow Copy Service

Disk Volume

Operating SystemStorage Array

VSS Writer VSS Requestor

Exchange Server Etc.

Your Backup Solution

VSS Provider

Volume Shadow Copy Service

Disk Volume

ESXi Host

Operating SystemStorage Array

Disk Volume

Virtual Machine

5

Microsoft VSS: What Every VMware Admin Needs to Know

With VMware vSphere, that mechanism can be your chosen backup solution. Figure 2 shows how a modern data protection solution that’s built for virtualization can fulfill the role of VSS Requestor, alerting VSS when backups are ready to begin. This integration enables your backup solution to coordinate backup activities for the VM, while VSS coordinates the activities inside the virtualized application.

One can further optimize backups with backup solution-specific VSS components. By leveraging the VSS framework inside each VM, additional intelligence can be added, such as log truncation of VSS-aware applications like SQL Server and Exchange.

Conclusion—there’s more (to VSS) than meets the eyeVirtualization can greatly improve how entire servers get backed up and restored, but without the right tools, virtualization can also complicate data protection activities. Applications inside VMs require quiescence to be backed up successfully. So do VMs. The right approach integrates a modern data protection solution that’s built for virtualization and includes the onboard coordination provided by Microsoft’s Volume Shadow Copy Service.

But it doesn’t stop there. The solution your VMware vSphere environment demands is one that can restore any application and any VM with the same granularity and confidence you’d expect for any file and folder.

6

Microsoft VSS: What Every VMware Admin Needs to Know

About the AuthorGreg Shields, Microsoft MVP and VMware vExpert, is an independent author, speaker, and IT consultant, as well as a Partner and Principal Technologist with Concentrated Technology. With 15 years in information technology, Greg has developed extensive experience in systems administration, engineering, and architecture specializing in Microsoft OS, remote application, systems management, and virtualization technologies.

About Veeam Software Veeam® is Modern Data Protection™. We believe today’s IT requirements have changed and that “3C” legacy backup problems—high costs, increased complexity and missing capabilities—are no longer acceptable for any organization. Veeam provides powerful, easy-to-use and affordable solutions that are Built for Virtualization™ and the cloud—a perfect fit for the modern datacenter.

Veeam Backup & Replication™ is VMware backup, Hyper-V backup, recovery and replication. This #1 VM Backup™ solution helps organizations meet RPOs and RTOs, save time, eliminate risks and dramatically reduce capital and operational costs. Veeam Backup Management Suite™ combines Veeam Backup & Replication and Veeam ONE™ in a single integrated solution to protect virtualization investments, increase administrator productivity and help mitigate daily management risks. Veeam Management Pack™ (MP) extends enterprise monitoring to VMware through Microsoft System Center. Veeam also provides free tools for the virtualization community.

Learn more by visiting http://www.veeam.com.

7

Microsoft VSS: What Every VMware Admin Needs to Know

Modern Data ProtectionBuilt for Virtualization

Powerful

Veeam Backup & ReplicationEasy-to-Use

To learn more, visit http://www.veeam.com/backup

#1 VM Backup for VMware and Hyper-VVirtualization changes everything – especially backup. If you’ve virtualized on VMware or Hyper-V, now is the time to move up to the data protection solution Built for Virtualization: Veeam Backup & Replication.Unlike traditional backup that suffers from the “3C” problem (missing capabilities, complexity and cost), Veeam is:

Join the 58,000 organizations who have already modernized their data protection with Veeam. Download Veeam Backup & Replication today!

Powerful: Restore an entire virtual machine (VM) or an individual file, email or database record in 2 minutes

Easy-to-Use: It just works!

Affordable: No agents to license or maintain, works with your existing storage, and includes deduplication, VM replication, Microsoft Exchange recovery, and more!

GOLD AWARDNEW

TECHNOLOGY

GOLD AWARDNEW

TECHNOLOGY