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Change Parallels Desktop 1.0's caching strategy Apps
In my day job I have to run Windows XP a lot. I've been using Parallels Desktop extensively for the past several weeks, and although I am really happy with it, something about it bothered me. Finally I realized -- it was causing a ton of VM paging on my brand-new MacBook with 2GiB of RAM! Something's just not right.

And in fact, there is a problem with Parallels Desktop 1.0. It uses Mac OS X's default caching strategies for huge files such as the operating system images (hard disk files) and SAV files (session saves). Over time, almost all of your RAM will fill up with data from these files, leaving little room for your other applications. If you've ever converted a hard drive image with Image Tool while doing something else at the same time, you'll know exactly what I mean.

I contacted the Parallels team last week to let them know about the problem, but haven't heard back from them at all. Perhaps they're all on vacation. Frustrated and needing a short-term fix to preserve my own sanity, I wrote PD Tweaker.

PD Tweaker is a tiny plugin for Unsanity's Application Enhancer that loads only in Parallels Desktop and Image Tool, and then tells Mac OS X to use a better caching strategy for these files. While I was in there, I noticed that Parallels was not flushing the OS files all the way to disk, leaving them a little more prone to data corruption in a power failure. So I fixed that too. You can read more about the rationale for both of these changes on the download page. The end result is a Parallels Desktop experience that is much smoother and does not slow your Mac down at all.

While the Parallels team may soon incorporate both of these fixes into their application, if you just can't wait until that point, then give PD Tweaker a try and watch how much faster your Mac feels when you run Parallels. It's freeware and the source code is available under a simple Creative Commons attribution license. Unsanity's Application Enhancer 2.0 is also required, but that's free, too.

[robg adds: I tested this on my mini, and it did indeed seem to make for a better Parallels Desktop experience, especially with many virtual machines running. You will have to use Application Enhancer, which may bother some people (AE allows code to be inserted into running programs that modifies their behavior). There is, however, a simple uninstaller if you want to remove AE from your system after testing PD Tweaker.]
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Change Parallels Desktop 1.0's caching strategy
Authored by: fitzage on Jun 26, '06 08:19:37AM

So far so good. I found myself before always having to quit either NNW or OmniWeb or both to free up plenty of RAM so my MBP wouldn't grind to a halt.

Now I have all my normal basic apps open (nothing like Dreamweaver or Photoshop) and it seems to be running at full speed (plus I still have over 200MB of free RAM, which I didn't expect to see).

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Change Parallels Desktop 1.0's caching strategy
Authored by: adams4 on Jun 27, '06 07:52:14AM

The problem I've had is with file sharing. Specifically, I've turned on Windows Sharing (i.e., SMB) on the Mac "side," and I've mapped a drive on the PC side (running Windows XP, SP2). (I haven't been using the Parallels Shared Folder feature, as I've found it slow and buggy.)

Anyway, the problem I've encountered is that sometimes, something is causing hundreds of smbd jobs to spawn (only two or three should be running). Eventually, the proc table can't spawn any more jobs, and unless I can quit a few running applications to get a terminal session going, there's no choice left but to reboot. Fortunately, I've managed to stop Parallels, quit apps, open a terminal session and sudo killall smbd to bring sanity back to my machine.

Adam Spector.

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Change Parallels Desktop 1.0's caching strategy
Authored by: markuswarren on Jun 27, '06 12:41:07PM
Hi, not sure if it'll help, but you mgith want to read this on about SMDB processes:

It principally mentions Tiger Server, but someone mentioned seeing a similar issue with Tiger clients, and the same fix for Tiger server worked for Tiger client.

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Change Parallels Desktop 1.0's caching strategy
Authored by: ntrsfrml on Jun 27, '06 08:31:42AM
Okay, i installed the AE and the PD tweaker. Do i have to enable the thing before i run Parallel's? Also what does Inactive ram means in OS X? Sorry i'm a new switcher


screenshot >

EDIT: My parallel copy is constantly taking 17-20% cpu usuage.. even when i'm not doin anything in Windows.. is this normal?

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Change Parallels Desktop 1.0's caching strategy
Authored by: Dolomite on Jun 27, '06 08:56:24AM

I also use Visual Studio 2005 extensively in Parallels on a MacBook with 2GB of RAM. I never really noticed a problem, but I installed this anyway. Two times Parallels locked up on me with a spinning beachball of death after I installed this and I had to force quit the session. Could that be related to installing this hack, or was it pure coincidence? I have since removed it and haven't seen it happen again. If it does then I know it didn't have anything to do with it, but just thought I would post this so other people can also keep an out out too.

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Change Parallels Desktop 1.0's caching strategy
Authored by: cynikal on Jun 27, '06 05:23:45PM

Not to sound paranoid, but is there a command line equivalent or another way of doing this w/o having to install a hack (App "Enhancer") and some mysterious plug in?

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Change Parallels Desktop 1.0's caching strategy
Authored by: stimpy on Jun 29, '06 12:05:34AM

My biggest problem with Parallels is that when compiling code using Visual Studio 2003, it is unbearably slow. I can't use shared folders since they are case sensitive so I'm using smb sharing, but I've heard that shared folders are slow too. Are there others in the same situation? Has anyone tried creating a shared FAT32 partition to share between OS X and parallels?

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Change Parallels Desktop 1.0's caching strategy
Authored by: Dolomite on Jul 01, '06 04:59:57PM

How much RAM do you have in your system? I bumped mine to 2GB and give XP 512MB and it seems to work pretty good. I am using Visual Studio 2005. If you only have 512MB n your Mac consider upgrading to the max.

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