Fusion - speed of disk I/O

[bceverly]

Hello everyone.

I'm struggling (and have been since day 1) with the speed of disk I/O in VMWare Fusion. I'm running the latest & greatest version on my Mac Pro:

• 8 cores at 3.0 GHz

• 16 GB of RAM

• Apple's RAID card

• 4 @ Seagate 7200.11 terrabyte drives

• RAID 0+1 configuration of the 4 drives above

From my perspective, this is a smoking fast machine and its behavior under OS X proves that out. Here's my problem, I do ASP.NET programming work on Windows so I am running either XP or Vista (doesn't seem to make much of a difference) in a VM running Visual Studio 2008 and SQL Server 2008 and my disk I/O is really poor. CPU and memory access are very fast, but that disk is a big bottleneck when I'm compiling code, etc.

Anyone know of any tricks to speed things up? I'm using "vanilla" VMs that were created by Fusion, I'm running the latest & greatest VMWare tools and I normally run a 40 GB virtual disk with somewhere between 2 and 4 GB of RAM and 2 cpu's dedicated to the XP or Vista install. 64-bit or 32-bit Vista doesn't make much of a difference either.

Any suggestions/help would be massively appreciated!

Thanks

[admin]

To me High Kernel percentages usually signify that the code is spending time in device drivers this leads me to believe that it is the Fusion disk I/O drivers causing the issue, but of course this is a guess.

We don't have "disk I/O drivers" on the host, we go through normal OS X system calls to access virtual disks and use whatever drivers come with OS X. It's possible that our access pattern triggers bad behavior, but it's not our drivers.

[wila]

Andy,

Of course I"m interested, better performance is always a goal :smileygrin:

Well I have to admit that initial file access on any file seems to be slower on VMware Fusion as on any of the other VMware products.

While I see some overhead on for example my VMware images on ESX in times of slower response while opening files, it is not nearly as slow as in Fusion.

Same for VMware Server and Workstation, file access time is pretty good in those products, it feels like native speed. While I love the Fusion product, I still can't say the same about its file open times.

In Fusion, once the file has been opened once, it is fine on the next time you open it, For example starting Word the first time is dog slow, when you close it and open it again, it starts within an acceptable time. This indicates either some file caching is going on (the Fusion Preferences > Performance setting takes care of this if I'm not mistaken) or that the VM is swapping. As this happens even with no other applications running, I'm inclined to believe that this is not a swapping issue.

The problem with this is that for jobs such as compiling, caching doesn't help much as you do not compile continuously, so by the time you compile again, most files are removed from the cache again.

--

Wil

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[BobTheDog]

Etung:

I understand you don't go directly to the disk but how do you interface to the OS X Virtual disks, would this show as Kernel time in guest os?

Andy

[wila]

Well I have to admit that initial file access on any file seems to be slower on VMware Fusion as on any of the other VMware products.

While I see some overhead on for example my VMware images on ESX in times of slower response while opening files, it is not nearly as slow as in Fusion.

Same for VMware Server and Workstation, file access time is pretty good in those products, it feels like native speed. While I love the Fusion product, I still can't say the same about its file open times.

Hmm... I take that "slower as workstation" comment back. Used to have an old macbook with only 2GB of RAM -as that was the maximum supported configuration on that model- so had to trim down memory on some of my VMs in order to even be able to run 2 VMs at the same time. Now that I've got another machine, I've added 500Mb more memory to the main guest that I run and things run much more smoothly. So I'd guess that I did see some side effect of swapping. Oops... not quite Fusion's fault.

--

Wil