Windows IT Pro is the leading independent community for IT professionals deploying Microsoft Windows server and client applications and technologies.
  
  
  Advanced Search 


September 29, 2008

Q. Is a Microsoft Volume Shadow Copy Service (VSS) snapshot the same as a virtual machine (VM) snapshot in Hyper-V?

RSS
Subscribe to Windows IT Pro | See More Backup and Recovery Articles Here | Reprints | Or get the Monthly Online Pass—only $5.95 a month!

A. No, they’re very different. A VSS snapshot is designed to create a consistent copy of a machine that can be used in a production environment. VSS does this by notifying running services that a snapshot is about to be taken, allowing the services to flush data from memory to disk. Flushing the contents of memory ensures that the information on disk is consistent and suitable for backing up.

A VM snapshot is designed to take a complete point-in-time copy of a VM. If the VM is running when the VM snapshot is taken, the snapshot is called an online snapshot. Online snapshots include a copy of the VM’s memory and process information in addition to the virtual disk’s contents and the configuration XML. If the VM isn’t running when a snapshot is taken, it’s an offline snapshot, and only the configuration XML and virtual disk contents are stored.

If an online VM snapshot is restored, the machine will start in the same state as when the snapshot was taken—including all processes and memory contents. Restoring processes and memory contents is fine in a test environment but isn’t suitable in a production environment. For example, a SQL Server instance that you restore using a VM snapshot from a previous point in production would still have active connections and running processes for machines that are no longer connected.

End of Article



Reader Comments

You must be a registered user or online subscriber to comment on this article. Please log on before posting a comment. Are you a new visitor? Register now




Top Viewed ArticlesView all articles
Command Prompt Tricks

One reader shares his tip for setting up the command prompt to reflect a remote path. ...

WinInfo Short Takes: Week of November 9, 2009

An often irreverent look at some of the week's other news, including some more Windows 7 sales momentum, some Sophos stupidity, Microsoft's cloud computing self-loathing, more whining from the browser makers, Zoho's "Fake Office," and much, much more ...

Understanding File-Size Limits on NTFS and FAT

A general confusion about files sizes on FAT seems to stem from FAT32's file-size limit of 4GB and partition-size limit of 2TB. ...


Virtualization Whitepapers A Business Case for Backup & Recovery for The Virtualized Environment

Related Events Deep Dive into VMware vSphere

Disk-to-Disk Grows Up

RUUP4IT? R2 Takes You Vertical and Virtual

Check out our list of Free Email Newsletters!

Windows OSs eBooks Understanding and Leveraging Code Signing Technologies

A Guide to Windows Certification and Public Keys

SQL Server Administration for Oracle DBAs

Related Windows OSs Resources Introducing Left-Brain.com, the online IT bookstore
Looking for books, CDs, toolkits, eBooks? Prime your mind at Left-Brain.com

Discover Windows IT Pro eLearning Series!
Clear & detailed technical information and helpful how-to's, all in our trademark no-nonsense format


Windows IT Pro Home Register FAQ for Windows WinInfo News
Europe Edition About Us Contact Us/Customer Service Media Kit Affiliates / Licensing  
SQL Server Magazine Office & SharePoint Pro DevProConnections IT Job Hound
Left-Brain.com Technology Resource Directory asp.netPRO ITTV Windows SuperSite 
 
 Windows IT Pro is a Division of Penton Media Inc.
 © 2009 Penton Media, Inc. Terms of Use | Privacy Statement