Saturday, November 29, 2008

Tips To Avoid Virtual Machine Issues

By Mike White

With the increasing popularity of Virtual Machines comes an issue that many may not be aware of. This problem is an age-old issue that has affected systems from the very early days of storage. It can cause hard drive failure leading to expensive data loss scenarios necessitating data recovery professionals. This problem is, of course, fragmentation.

Just like any other software virtual machines still require (unless you have a very specialist setup) to be run from the hard drive, which is still and probably will remain so for many years to come, the slowest part of your system. Drives can be broken in sub parts know as partitions which can then be utilized as a different drive so to speak but hard disk fragmentation is still an issue.

Fragmentation is where a file is split into multiple components by the operating system to allow it to fit in available space of the hard disk drive. When you are already running one operating system, and fragmentation becomes an issue, running another highly fragmented system on top of this causes a tremendous slow down in performance.

Fragmentation will not only slow down your computer or server but due to the excessive and unwarranted extra movement of the heads, the life of your storage device(s) can be seriously reduced. The problem is not only limited to single drives however, even if you have a very well specked raid set up, fragmentation can get so severe that the only viable option is data recovery or server rebuild.

Operating systems handle fragmentation in different ways. Microsoft Windows, for example, pays little or no attention to the degree of fragmentation on a storage device, whereas Mac OS X goes some way to helping by automatically defragmenting files under 20 MB in size. Other Operating Systems handle file fragmentation in various ways, with varying levels of success.

Windows does ship with its own on board defragmentation tool but many would consider it a mere tick in the box as running the utility will mean that the hope of having a usable system in the meantime is improbable, and defragmentation could last for many hours or even overnight in some cases, so what are the other options.

Use automated defragmentation routines: Dependent upon your OS you can normally, either directly in the OS itself or via third party software; schedule defrags to run at times convenient to yourself.

Invest in dedicated hardware. Not the cheapest solution but for business and power user home systems probably the most sensible route. Dedicated hardware could be an additional hard drive (internal or external) a dedicated raid array or even an SSD device. The actual solution will depend on how mission critical the application actually is. - 15433

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