HP Data Protector Zero Downtime Backup (array-based snapshots)
Below is an overview of each of these methods – and a few important things to consider along the way:
Backup agents inside the virtual machine
This is probably the easiest and least expensive way to back up VMware virtual machines. Administrators install a Data Protector online backup agent inside each virtual machine, just as you would in the physical world. This approach delivers consistent backups, which means that the data is synched with the application upon restore, since the Data Protector backup agent talks directly to the application (VMware does not yet interface fluently with applications). However, using this method, server performance is impacted performance as all the other virtual machines on that physical host vie for resources. The more virtual machines you load on a physical server, the worse the problem becomes. As a result, customers can wind up limiting their ability to “virtualize” their servers.
VMware ESX server snapshots
VMware ESX Server has the ability to take snapshots of data on the virtual machine. A snapshot creates instant, point-in-time copies of data on a per-volume basis and it's an easy way to retrieve data that may have been deleted or changed accidentally. Snapshots keep track of the information that’s changed in between snapshots and the current backup. Each snapshot is then stored on disk or tape for recovery as needed. To execute an ESX Server snapshot, you either use the command line interface or launch the separate VMware Virtual Infrastructure client. This method does give administrators the ability to do incremental backups for virtual machines, but it both impacts server performance and yields only crash-consistent data upon recovery. However, for many customers this is an acceptable option. Data Protector customers use the Data Protector GUI to execute an ESX Server snapshot. Because most organizations are using a combination of physical and virtual servers, this allows you to simplify your backup and recovery operations in both environments from one unified interface without scripts or launching separate clients or 3rd party utilities.
VMware Consolidated Backup Image- and File-level backups
VMware’s Consolidated Backup software resolves the server performance issue and provides full and incremental backups of virtual machines. VMware Consolidated Backup software is loaded on a dedicated server – or proxy host – and you can run either an image or file-level backup. Because the proxy host offloads the processing from the virtual machine, you overcome the server performance issue. However, in either case backup administrators are still left with application crash-consistent data that once they restore. This method also requires that a dedicated host be added in order to run the backup process. HP Data Protector is closely integrated with VCB, and you can manage both VCB file and image-level backups from the same Data Protector GUI you use to manage all of your backup processes – both physical and virtual. For either VCB file or image-level backup, Data Protector talks with the VCB proxy host to manage the process.
Data Protector Zero Downtime Backup
Data Protector’s Zero Downtime Backup agent is currently the only way to avoid server performance degradation in a virtual environment AND ensure application consistent backups – all from one interface. Data Protector Zero Downtime Backup utilizes replication techniques (such as split-mirror, snapshot or snapclone) to move the processing load off of the virtual machines and onto the array. A copy of the data is created on the array at very high speed. Data Protector then performs backup operations on the copy, rather than the original data. This “staged backup” process allows you to keep your business applications online 7x24. The Data Protector Zero Downtime Backup agent is also “application aware”, which means it provides you with a consistent backup in VMware environments. There’s no need to run tools to check the database integrity or delete corrupted data. Zero Downtime Backup allows you to perform backups more frequently than once a night and, in fact, expands your backup window to all day, every day.
You’ve probably seen the February 2010 announcement from VMware heralding the end of life for its Consolidated Backup (VCB) framework – and their intention to rely on the new vStorage APIs for Data Protection (VDAP) in vSphere 4.1 once it’s released.
HP will provide support for the new vStorage APIs for Data Protection (VDAP) in the current Data Protector software version after VMware releases vSphere 4.1 (find an overview of VMware data center products here). For more information on Data Protector support for vStorage, check out “Much Ado about vStorage” on HP’s Information Faster blog at: