Defrag from Dual Boot configuration

[greybat]

(Hope this has not appeared earlier - I searched but did not find!!!)

I notice posts advising running a defrag from safe mode because less Windows files are in use, but it's slower. Is it, then, a good idea, if you have a Vista and XP dual boot configuration, to defrag the Vista drive while running XP and vice versa?

Thanks.......

Graham

[jeroen]

Yes, you can do that. The Windows defragmentation API on Vista has some enhancements that will allow it to defragment and optimize more files than XP. You can run JkDefrag normally if the "other" volume is mounted, but JkDefrag can also process unmounted volumes. You will need to know the volume name, which is a long string something like "\\?\Volume{35683226-d2c4-11dc-9740-806e6f6e6963}\". You can find this with the Windows commandline "mountvol" command. And then run JkDefrag with that name as a parameter, for example "jkdefrag.exe \\?\Volume{35683226-d2c4-11dc-9740-806e6f6e6963}\".

Warning: never hibernate, always shutdown. If you change a hibernated disk (system or data disk) in any way while in the "other" boot then you are in big trouble.

[boco]

The Hibernate problem only applies to external solutions (like LiveDiscs, Bart-PE etc.). If you have dual-boot and hibernate one OS, you can't select the other. Windows bootloader won't show you the start menu and goes straight to resuming the OS. Even my mainboard detects the Hibernate status and displays a logo 'RESUME FROM HIBERNATION'.

Short: You can't boot the other OS while one is hibernated, at least for Windows OS and Windows bootloader. Don't know about Grub, LiLo etc.

[jeroen]

The Hibernate problem only applies to external solutions (like LiveDiscs, Bart-PE etc.).

Not quite, because JkDefrag can process unmounted volumes, like I just explained. I think the hybernation problem can also apply to other volumes than the system volume, if system files have been relocated to that other volume. For example the pagefile.

By the way, JkDefrag has a build-in protection for this problem and when it detects hybernation on a volume it will refuse to process that volume. But it is best to avoid the problem altogether and never use hybernation in the first place. See the JkDefrag homepage, the "How do I defragment C:\hiberfil.sys" question, for instructions on how to disable hybernation forever.

[greybat]

Thanks for the feedback. Maybe the best solution is a full defrag from Vista, then defrag the Vista volume again (always mounted, in my case) from XP, which I actually rarely use, preferring a virtual XP box for the few times I need to check something out there. Which raises another question (which probably should be another post): Presumably there is little point in defragging a virtual hard drive. True or false?!

BTW, I never hibernate, and rarely sleep ( ). In my case, I find Vista often does not restart properly from these states.

[jeroen]

Presumably there is little point in defragging a virtual hard drive. True or false?!

False. Virtual drives are pieces of harddisk on the server, and therefore benefit just the same from defragmentation and optimization. If a virtual machine moves the virtual harddisk heads in case of a fragmented file, then this results in just as much real harddisk movements on the server. Virtual disks should be defragmented twice, once on the server and once inside the virtual machine.