Backing Up on VMware

Thursday Jan 18th 2007 by Drew Robb

VMware Consolidated Backup promises to make backup easier for virtual environments, but time will tell if it lives up to that promise.

VMware Consolidated Backup (VCB) was released last June to make backup easier on a VMware platform. That was followed by a cackle of vendor announcements outlining their support for VCB as well as various ways they could improve upon it. Some wondered, therefore, was there something wrong with VCB itself?

"The main challenge of VMware Consolidated Backup today is to simply understand how it works and what an administrator needs to set it up," says Azeem Mohamed, senior director of marketing and products for Vizioncore of Buffalo Grove, Ill., a vendor that has released a backup tool that works in conjunction with VCB. "Once an administrator has this information, the rest is very straightforward."

The overall thrust of all this VMware backup activity, then, appears to be an effort to improve backup as a whole by harnessing virtualization environments.

"Time-consuming and labor-intensive backup and recovery processes have frustrated customers for years," says Arun Taneja, founder and consulting analyst at the Taneja Group. "VMware Consolidated Backup eliminates the backup load from production servers while enabling faster recovery of entire virtual machines."

Tradition Meets Virtual Backup

Traditional backup meant installing agents on each server, temporarily suspending applications from running on physical servers until the backup agent can send data over the network to a backup disk or tape. Those applications would resume once the backup was completed.

Thus backup agent software runs on each system to read and store the important data to an external repository. This scenario, however, introduces several bottlenecks. Backup administrators need to spend time ensuring that every system has a properly functioning backup agent. This entails reading through log files from backups to ensure that each agent successfully does its job, taking up a significant amount of administrator time.

These agents use resources on the system, thereby reducing the ability of that system to perform its normal work. Further, backups normally need to be scheduled to start and complete during off hours to avoid conflict with the systems' normal workload. But as the amount of data to back up continues to grow, it becomes increasingly difficult to complete a backup within a shrinking backup window.

"With VMware Consolidated Backup, you can reduce or eliminate these bottlenecks," says Bogomil Balkansky, director of product marketing at VMware, an EMC company.

VCB builds on the VMware Infrastructure 3 (VI3) release, which included VMware ESX Server. It is designed to simplify data protection by offloading backup to a centralized server. This enables ESX Server to run more virtual machines by reducing its load, and it eliminates hardware dependencies and enables backup to occur safely during production hours. ESX Server creates a snapshot of a virtual machine's disk. A driver on a backup proxy server mounts the snapshot, and third-party backup software running on that server backs up one or more virtual machines to disk or tape.

The benefits are said to be faster full-system recovery and simplified backup. Instead of installing backup agents on each virtual machine, they only need to go onto one centralized server. Thus system resources on the other virtual machines are freed up. And because VBC uses a snapshot of a systems' data, it does not require a lengthy backup window. Further, the backup can be performed while the system continues to do other work. As a result, backups can be scheduled to run throughout the day rather than just at night.

VMware remains, however, a largely Windows-centric platform.

"VMware Consolidated Backup enables image-level backups for both Windows and Linux systems, but at this time can only provide file-level backups for Windows systems," says Balkansky.

Image-level backups essentially treat a disk as simply a sequence of data without trying to understand how that data is organized into files and directories. File-level backups, on the other hand, actually look at the individual files on the disk as files. Since backups using VCB use a Windows server as a backup proxy server, it can read Windows files, but can only see a Linux file system as an image.

Joining the Bandwagon

Several vendors have already jumped onto the VCB bandwagon. CA, CommVault, EMC, IBM Tivoli, Symantec and Vizioncore are among those that have announced compatible offerings that back up virtual machines. Some of these claim to do far more than the basic backup functions offered by VMware.

"Backup is becoming more important to minimize any risk of having all of your application eggs in a single virtualized server basket," says Greg Schulz, founder and senior analyst at StorageIO. "There are so many different types of backup, replication and related data protection vendors, each with their own unique capabilities to differentiate their products from others. As they adopt support for VCB, its only natural that we see claims and counter claims about how their offering is different."

Vizioncore, for example, has just released esxRanger Professional 3.0, which integrates with VMware Infrastructure 3 and VMware Consolidated Backup to enable LAN-free high-speed backups of virtual machines. The idea is that while VCB uses the network to function, esxRanger Professional eliminates the network load, as well as the traffic on the proxy server.

A memory extraction engine bypasses the need to stage data on the proxy server. According to Vizioncore, this increases the speed of the backup process by up to 300 percent and cuts down on disk storage requirements for snapshots. esxRanger Professional 3.0 can either be used to restore an entire virtual machine or specific files. Pricing starts at $500 per CPU socket.

"A proxy host connected to the SAN is able to read the data of the virtual machines on the SAN and export that data over the Fibre Channel infrastructure, thus eliminating the need to traverse the network," says Vizioncore's Mohamed. "By utilizing this functionality, esxRanger Professional is able to perform a backup with no overhead on the VMware Infrastructure 3 host, virtual machine or network infrastructure."

Additionally, esxRanger Professional intercepts the data stream in memory prior to VCB writing data to disk. This allows administrators to pass the data stream through compression and differential engines as well as redirect the data stream to the location of their choice.

The administrator, however, must first set up the virtual infrastructure to leverage a SAN architecture, if they have not done so already.

"For those environments that currently do not leverage the SAN, this will be a major architectural modification," says Mohamed. "However, we have found that administrators are already either deploying VI3 with the SAN architecture or in the process of upgrading to VI3 from ESX Server 2.X, the administrator is adding the SAN architecture as part of the migration upgrade from ESX Server 2.x to VI3."

As well as the performance boost by moving to a SAN, new add-on features within VCB such as Distributed Resource Scheduling and VMware High Availability appear to be tempting some companies to test the SAN waters in conjunction with VCB.

Too Early to Tell

All this sounds good, of course, but it remains to be seen just how well it works out in the real world. At this time of writing, Vizioncore had just released the product from beta and was unable to come up with a customer willing to talk.

As the year progresses, enough implementations of virtual backup tools from Vizioncore, VMware and other vendors will have taken place to obtain a clearer picture of its effectiveness in an enterprise environment, as well as any bugs.

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