Tips For Virtual Machines
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.
If you are fortunate enough to have very deep pockets then you may be using SSD’s or solid state drives. These still remain expensive and are out of the reach of most users who still have to rely (although getting much faster) on the slowest and some would say the most vulnerable technology in your computer- the hard drive. Hard drive fragmentation can cause problems with virtual machines and in some cases even data loss.
Fragmentation occurs on all hard drives and is part of the way the operating system stores the data on a disk. It won’t lay it down nice and neatly in one continuous block, but will lay it wherever there is a space. One file could literally be split into many separate places on the hard disk and this is fragmentation. If you have one OS running it can be bad but if you are running virtual machines the problems is far more serious.
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.
Utilizing defragmentation tools can help to alleviate the problem but often the use of some of these tools is very invasive and will render your system virtually unusable while they are running so what other options do you have.
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.
Use separate hard disks for your Virtual Machine software. While this may appear to fly in the face of VM’s in the first place, having a robust and business capable solution is in most cases the driving factor. Some astute companies will even have a dedicated hard disk array solely for the purpose of running VM software if there is a business case for it.