VM /ETC

Fluid Operations, owner of the eCloudManager Project, has open sourced it’s VMFS Driver Project. The driver is actually an application that can run on Linux, Windows or any operating system that supports Java. It apparently provides read only access to VMware VMFS volumes.

The VMFS driver has been developed for use in fluid Operations’ eCloudManager Storage Edition which is described as:

“… the industry’s first solution which allows for managing CPU and storage virtualization through a single pane of glass. This solution allows high-performance applications to be rolled out on an enterprise cloud utilizing multi-vendor server virtualization and storage technologies. This first release orchestrates VMware Virtual Infrastructure as server virtualization and NetApp filer technology as storage.”

eCloudManager is in beta, but is available both as a plugin for VirtualCenter or as a web interface.

The implications of the open source availability of the VMFS driver are huge in my opinion. For example, a VMFS driver could allow the creation of a liveCD that would be able to access virtual machines on a failed ESX host. Those stranded VMs could then be transferred to another working ESX host. There are also numerous other VM backup, disk analysis, and monitoring possibilities from a non VMware server.

Here’s some more information from the fluid Operations Community Page:

“This driver enables read-only access to files and folders on partitions formatted in the Virtual Machine File System (VMFS) by VMware. VMFS is a clustered file system that is used by the VMware ESX hosts to store virtual machines and virtual disk files. The VMFS driver is developed and maintained by fluid Operations and is included in upcoming releases of the eCloudManager product, where it is used to allow enhanced features like offloaded backups of virtual machines hosted on VMware ESX hosts. The VMFS driver comes with a command line interface (CLI) to mount and analyze VMFS volumes. The VMFS driver was tested on Linux and Windows based hosts, but should work on any platform that supports Java.”

The VMFS Driver Java application is available for download via it’s Google Code Project page. There is also a FAQ with the following additional information (and more – go check it out) about the VMFS driver.

Why is it useful?

Accessing offline (e.g. backed up, unused, legacy) VMFS volumes is not a trivial task. Especially if there are only non-VMware hosts around, there is no open way of accessing the files. But even if VMware hosts are available, one needs to take care of “volume resignaturing” and other challenges.

fluidOps strives for openness and therefore provides this technology as a free solution to make backups and other offline VMFS volumes readable, from any environment.

Do you have the VMFS specification?

No. The driver is the result of extensively analyzing the on-disk format, and comparing changes after certain file system operations. This is an ongoing process.

Do you plan to add write support?

Writing into existing files (i.e. virtual disks) is easy and will be included soon. Creating files and folders, or changing file allocation, is hard, and requires a lot more work to be done.

This is no “driver”. It is just a Java app!

Right and wrong:

• Right, it is no driver running in kernel space. It is a user space file system library.

• Wrong, because you can easily hook for example a WebDAV frontend into the VMFS driver lib, making it a “full” file system driver. Then you can regularly mount the VMFS as a file system under the major operating systems and use all regular file operations, from all applications. (Expect a checkin soon that enables this feature…)

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