Defrag with VM is VERY Slow.

[SCPhil]

I had the opportunity (requirement, really) of needing to defrag the vm partition (15 gb of 20).

Now, this is a dog most of the time on xp pro systems, however, in the Fusion VM world this is extremely painful. All life, as we know it, ground to a halt. The process worked, the disk was extremely fragmented (since we were on a Mac, we had stopped paying attention to such mundane things), but no other activity took place until this process was completed, many, many minutes.

As I have a Mac Book Pro, 2.4 GHz, 3 GB 667 Mhz Ram, I was very disappointed in this file processing with vm. This was one of two items that caused me to question whether vm on a mac of production Windows app is truly feasible.

Is there a good reason/cause for this in the vm world? Does Parallels do a better job?

Many thanks for any comments.

[admin]

How long is "many many minutes"? For example, I was surprised by how long discarding a snapshot took until I did some math: my MacBook's drive was transferring data at about 16 MB/s, so running though a 15 GB snapshot would take (15 GB/(16 MB/s)) = 16 minutes just to copy the data around. 16 MB/s is at least in the right ballpark for a laptop drive. I would imagine defragging could also have to run through a good chunk of disk.

[WoodyZ]

Defraging under normal conditions is a slow process! It is normal on a Virtual Machine to be even slower as there are other processes running as well that can usurp the CPU from focusing only on defragging. BTW defraging in Safe Mode tends to be faster than Normal Mode Windows.

FWIW In spite of Apples position on whether or not then HFS+ File System prevents fragmentation I can say beyond any doubt that an HFS+ formated disk gets just as fragmented as any Windows base file system disk gets and the proof is in what iDefrag reports both before and after defraging an HFS+ volume!

[SCPhil]

The defrag took 45-50 minutes (as best I can guess).

The problem was, while this was happening, I was not able to do any other items -- as I was on the clock at a customer site, this was an issue.

The activity monitor listed only 35-30 % cpu tied up with fusion. The real issue was, I guess the disk activity.

It was similar to when I sometime turn on the wireless connection and my mouse, et. al. stops working for this few seconds. In this case, the few seconds went to minutes to 10's of minutes, etc.

Thank you for the comment.

[SCPhil]

Thanks for the comment. If I need to do this again during "working" hours, I will use the safe mode.

Phil