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This paper provides general information for using Data Domain deduplication storage systems to backup virtual machines deployed with VMware Infrastructure 3 (VI3). Topics include an overview of VI3 components and various methods of backing up data in VMDK images and Guest OS files for discrete recovery – either locally or remotely in a DR site. But the central focus is on which backup approach is best using specific criteria, and by extension, how can Data Domain deduplication storage systems be leveraged to assist in online restore and replication to a DR site.
VMware is the predominant method in the open systems world for creating multiple virtual machines in a physical computing system. By separating virtual systems from physical constraints, they become easier to manage. Consolidation helps take greater advantage of powerful server assets which can contribute to supporting green initiatives.
But VMware sites also tend to create more storage to manage and protect than their physical counterparts. By making it much simpler to multiply servers, it also becomes more likely that their storage footprints will multiply. This is significantly visible in backing them up. For example:
4 Multiple similar VM environments, times multiple storage image versions for protection and DR, can equal much larger storage than when servers were more expensive to clone.
In backing up VMware environments, restore needs may include both full VMDK images as well as individual file restores to the Guest OS. Backing up both VMDKs and Guest OS files can offer optimum protection, but the data is highly redundant. With normal backup target storage, it would mean that many more tapes or that much more disk storage capacity.
Fortunately, with Data Domain systems as the target storage for VMware environment backup, those similar files would be deduplicated at high speed. All of the common data sequences are pooled to the smallest reasonable storage footprint, for on site protection and replication to a DR site. Where most file system backups result in 10x-30x data reduction on a Data Domain system, VMDK-inclusive backups commonly offer 40x to 60x reduction. For more background on Data Domain’s award winning deduplication storage system, please see also www.datadomain.com.
When using Data Domain storage with well-understood best practices for backup and taking snapshots in VMware, a deployment can simplify management of consistent images. Once stored, the images are ready to restore, locally or, with optimized deduplicated replication, at a remote DR site. This paper describes best practices for managing these synergistic technologies together.
While vendor references and script examples are included, these are examples only and should not be considered definitive or guaranteed by Data Domain.
For a proper introduction to VMware components, terminology and use, please refer to the wide variety of information on www. vmware.com.
Briefly: VI3 is a bundled product with four components: Virtual Infrastructure Client (VI Client), License Server, Virtual Center Management Server (VC Server), and the ESX Server Console (part of the ESX Server).
An ESX host, which has a hypervisor kernel (vmkernel), runs VMs (Virtual Machine). The service console is actually just a VM itself, which is granted special privileges to access the configuration of the ESX host machine. The figure below shows an example of a typical VI3 deployment with 2 VMs.
Each VM has one or more of its own disk images (VMDK). The collection of VMDKs is managed by the VMFS file system and the ESX service console, a VM with special management privileges. VI3 also includes a new package, VMware Consolidated Backup (VCB). VCB allows a more centralized approach to off-ESX-host backup, using a special purpose Windows proxy server that accesses ESX data independently. When deployed appropriately, VCB offers many scalability advantages for backing up VMs and VMDK files.
A specialized backup proxy server has access to shared VMDK files and their Guest OS file systems. Using this proxy system, backup software can capture VMDK and Guest OS file backups with low application-VM impact and only moderate impact on the ESX server. It will require a proxy server.
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