New VMware APIs are making snapshots and backups faster and easier for IT.

Jasmine McTigue, Principal, McTigue Analytics

July 20, 2012

3 Min Read

InformationWeek Digital Supplement - August 2012

InformationWeek Digital Supplement - August 2012

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IT teams that have gone big on virtualization can take advantage of advances that simplify the process of backing up virtual machines.

VMs are composed of fixed configuration and disk files, so it's easy to grab a copy of a machine's resource profile, snag the associated disk files, and spin it up anywhere, anytime. And VMware and Microsoft have improved this functionality.

Do you store your VM images on a SAN? Want to back up your machines while they're still running? Snapshot-compatible backup applications that leverage vendor APIs to do the heavy lifting are available for the major hypervisors. They make API calls to take snapshots of VMs prior to starting the backup process. Changes are redirected to a change file instead of the original volume. The machine is backed up, even if clients are using it, and the snapshot is destroyed.

VMware has performed backups this way since ESX 2.0, but it required the use of a VMware Consolidated Backup proxy server. This meant IT had to deal with tedious configuration requirements, and the underlying storage system was saddled with a significant amount of read I/O during backups.

Users griped, so VMware has eliminated VCB in favor of an integrated API called vStorage APIs for Data Protection. VADP is invoked directly by a backup application and is a configuration-free feature of vSphere.

Third-party virtualization backup providers such as Veeam have taken full advantage of VADP and its Microsoft equivalent, Volume Shadow Copy Service, to deliver low-cost, highly effective, VM-level backup at a reasonable price.

Other Capabilities

Virtualization APIs can also grab flat-file backups from guest virtual machines, and products that already excel at flat-file backups can leverage the APIs to do so better and with a smaller footprint. But most exciting is underlying storage's involvement in the backup process.

The latest storage APIs from VMware, and to a lesser extent Microsoft, use the horsepower of the storage arrays to make copies of data to be backed up. This approach works provided the storage array has enough spare capacity to accommodate the I/O. Doing the backup itself requires an API-compatible backup product for VMware. Acronis, CommVault, EMC, Hewlett-Packard, Quest, Symantec, and Syncsort are API certified. Using hardware-assisted copy requires a SAN that's compatible with vStorage API for Array Integration. Three vendors have VAAI-ready SANs, according to the latest VMware hardware compatibility list: FalconStor, LeftHand, and HP.

Other advances are transforming backup. For instance, imagine running traditional network- or agent-based backup over the internal hypervisor instead of across conventional network links. VMware's Virtual Machine Communication Interface allows machines on the same host to read data from one another at the speed of the internal machine bus. It's fast, particularly for large transfers or where the data is in running memory. One example is SQL Server, which is designed to keep as much data as possible in memory for faster reads and queries.

Note that you'll need to upgrade to vSphere 4 or later to take advantage of these APIs.

Jake McTigue is president of McTigue Analytics.

About the Author(s)

Jasmine  McTigue

Principal, McTigue Analytics

Jasmine McTigue is principal and lead analyst of McTigue Analytics and an InformationWeek and Network Computing contributor, specializing in emergent technology, automation/orchestration, virtualization of the entire stack, and the conglomerate we call cloud. She also has experience in storage and programmatic integration.


Jasmine began writing computer programs in Basic on one of the first IBM PCs; by 14 she was building and selling PCs to family and friends while dreaming of becoming a professional hacker. After a stint as a small-business IT consultant, she moved into the ranks of enterprise IT, demonstrating a penchant for solving "impossible" problems in directory services, messaging, and systems integration. When virtualization changed the IT landscape, she embraced the technology as an obvious evolution of service delivery even before it attained mainstream status and has been on the cutting edge ever since. Her diverse experience includes system consolidation, ERP, integration, infrastructure, next-generation automation, and security and compliance initiatives in healthcare, public safety, municipal government, and the private sector.

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