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Storage built for virtual servers
A number of startup storage vendors have rolled out hardware and software storage solutions specifically designed for virtual server environments. These include Atlantis Computing Inc., SolidFire, Tintri Inc. and Virsto Software. In essence these products are architected to address the issues described here, including random I/O challenges.
Managing dynamically changing virtual environments to optimize capacity and performance can be a time-consuming process. As virtual environments scale and mature, there’s a need to move toward more automation of manual optimization processes. Hypervisor vendors are starting to include capabilities in their products that allow some of these features to be semi-automated, reducing the onus on the administrator to continually tune the storage environment. In vSphere 5, VMware introduced Storage Distributed Resource Scheduler (SDRS), which provides some degree of automation of storage allocations. SDRS provides automated initial placement of VMDKs, automated migrations of virtual machines to meet capacity and performance goals, as well as affinity rules, ensuring, for example, that high I/O virtual machines are placed on separate hardware.
The move to more automated storage management will be an absolute requirement as
Don’t forget backup
Backup always seems to be treated as a poor relation in storage management; however, it’s of vital importance for delivering high-availability storage environments. In virtual infrastructures, traditional backup solutions aren’t the most efficient way to back up and restore data, and other techniques can be used to optimize the backup and restore process.
In block storage deployments, traditional backups use the host itself to back up data. This is because the storage array has no awareness of the format of data on a LUN. The host places the file system onto the LUN, so the backup software relies on the host to provide a stream of files for backup.
On all virtual platforms, a VM is stored as a file or series of files, even when using block-based storage arrays. This makes the backup process easier, as backups can be taken simply by taking a copy of the files that make up the virtual machine.
Some hypervisor vendors, such as VMware, offer APIs that allow third-party software to view changed block data within the virtual machine itself, providing a highly efficient way of backing up only those files that have changed since the last backup was taken. All hypervisor vendors also provide the ability to snapshot virtual machines. Although this results in a “crash consistent” copy, in some instances, with agent software, the snapshots can be coordinated with quiescing the host file system to allow consistent snapshots to be taken.
Storage tools will evolve
Storage continues to be a key feature in deploying scalable virtual infrastructures. As these environments scale and mature, storage administrators will need to employ tools and techniques such as automation and visualization software that will allow them to meet the challenges of an ever integrated IT world.
BIO: Chris Evans is a UK-based storage consultant. He maintains “The Storage Architect” blog.
This was first published in April 2012