Menu
Virtual machines need defragging too

Virtual machines need defragging too

An Osterman Research white paper argues for defragmenting virtual machines

Weighing in on a seemingly perennial question asked by system administrators, IT analysts Osterman Research is recommending that virtual machines be defragmented just as often as physical drives.

"The need for defragmentation is even more acute in virtual environments," stated a newly posted white paper co-authored by Osterman and disk management software vendor Diskeeper. "Physical hardware in a virtualized storage environment must support more operating systems and so can undergo even more disk access and more stress than in a non-virtualized environment."

[Read Computerworld Australia's storage virtualization buying guide]

Disk fragmentation occurs when data is continually written and rewritten to a disk, which can cause data to be scattered across different physical sectors of the physical drive when there is not enough contiguous space to write a file in one uninterrupted block. As a result, when a file is called, the disk must do more work recollecting the bits of the file from different locations, slowing performance.

Windows, as well as third-party software firms, offer defragmenters to reassemble fragmented files. Fragmentation is not as large of a problem on Unix systems, due to the way that the OS writes files to disk.

According to the paper, virtual disks can become just as fragmented as physical disks. For instance, a single file on a virtual disk may be split into four fragments, and the virtual disk itself may be split into another three fragments on the physical disk itself. The cumulative effect of fragmentation on both layers reduces system performance considerably.

"Disk I/O in one virtual machine has a cascading effect on disk I/O in other virtual machines, and so the problem of excessive disk I/O in virtual machines is, in fact, even worse than what would be experienced in a physical disk environment," the paper states.

Not surprisingly, Diskeeper offers virtual disk optimizer software, V-locity, which can prevent virtual machines from becoming too fragmented. But both Microsoft and VMware have recommended defragmentation in various support forums as well.

Joab Jackson covers enterprise software and general technology breaking news for The IDG News Service. Follow Joab on Twitter at @Joab_Jackson. Joab's e-mail address is Joab_Jackson@idg.com


Follow Us

Join the newsletter!

Error: Please check your email address.

Tags application virtualizationConfiguration / maintenanceOsterman ResearchmaintenanceDiskeeperhardware systemsStorage virtualizationVMwaresystem managementvirtualizationServer VirtualizationMicrosoftdesktop virtualizationsoftware

Featured

Slideshows

Channel celebrates as HP marks 50 years in NZ

Channel celebrates as HP marks 50 years in NZ

HP marked 50 years in New Zealand at an event in the vendor's Auckland's headquarters last night, with a host of key channel figures coming along to celebrate. Photos by HP.

Channel celebrates as HP marks 50 years in NZ
EDGE 2017 - Icebreaker Sessions round 2

EDGE 2017 - Icebreaker Sessions round 2

EDGE guests experience the value of networking at the second round of Icebreaker sessions.. Photos by Maria Stefina

EDGE 2017 - Icebreaker Sessions round 2
EDGE 2017 Dinner Under the Stars

EDGE 2017 Dinner Under the Stars

EDGE's Day 2 keynote and breakout sessions were followed by the Dinner Under the Stars. Over 300 people were present to enjoy a seafood feast and lots of excitement at Hamilton Island's Bougainvillea Marquee. Photos by Maria Stefina.

EDGE 2017 Dinner Under the Stars
Show Comments