Stable enough to get rid of win box?

Discussion in 'General Questions' started by want2get, Apr 12, 2007.

  1. want2get

    want2get Bit poster

    Thanks for the help I received in my other thread.

    I don't currently have a mac to test parallels on I'm in the process of seeing which model will fit my needs best, which leads to my next question :).

    Is parallels stable enough for me to get rid of my winxp box. I have 1 program that requires windows to run connected to my office vpn. It is pretty much connected 24/7 except for the few times a week something screws up with windows and I need to reboot. My idea situation would be 1 vm running this needed program thou my office vpn. 1 vm running my other xp apps like office ect. This way I can consolidate the 3 pc's I have now running into 1.

    I would love to get a mac pro, but if parallels isn't stable enough or just isn't meant to be a win box replacement I'll go with the imac.

    Thanks again for any advise or help you can offer in helping me make this decision
  2. mmischke

    mmischke Hunter

    I make my living as a Windows software developer. I've been doing all my work on XP running under Parallels on my Mac mini for several months, and I haven't had a single problem. I attribute much of my success to avoiding the more 'cutting-edge' features, like Coherence and USB 2.0 (although I did play around w/Coherence for awhile and didn't encountered any problems).

    Your use case seems ideally-suited to XP under Parallels, especially since you're considering a powerful machine. You'll probably be fine with even a lower-end Mac Pro. They have a minimum of four CPU cores. I'd go for at least 4 GB of RAM (2 might not be enough if you want to run two virtualized XP sessions simultaneously, as well as OS X). One last thing I'd consider is a second hard drive. Placing virtual hard drive files on a different physical drive than the OS (or Parallels) will speed things up nicely (this is true for any virtualization package - not just Parallels).

    Be sure to feed XP ample RAM, just as you'd do for a physical machine. I'd expect that the sweet spot for each VM would be between 512 MB & 768 MB, but you'd have to experiment a bit.

    BTW - I'm not sure which VPN client you're using, but I use Windows PPTP and Cisco all the time. I can't speak for any of the others. Also - if your Mac goes to sleep, you'll obviously lose network connectivity. Since you have a 24x7 app, you can play with OS X's power settings to minimize energy consumption, while not going to sleep, when you're not actively using the machine.
  3. psyfil

    psyfil Member

    No, No, No!


    No No No!!!!!!!!!!

    This was my original fantasy when getting involved with Parallels. While I can generally run my business/practice on one machine--an IMac 24" 2.33 ghz, 3 gigs of RAM, 500mb hard disk, there are certain things that just do not work and require me to keep around both an old Windows desktop and laptop for programs I sometimes must run.

    In particular if you have specialized programs that require setup.exe files to load, I find the Virtual Machine often gives a Fatal Error in the Virtual Machine trying to install these programs. This has been reported to Parallels many times with no fix so far--so I must keep the windows boxes around to run these.

    I needed to go up to 3gigs of RAM because with any less, Parallels made the Mac side slow and it tended to lock up and need to be re-started. I still have some kind of hangup about once a day.

    While things are going 'OK enough' in this experiment, it is not ready for Parallels to do everything you might want a Windows box to do.

    They are starting a new more refined Beta program that may help but not for awhile. I suggest waiting or making sure your particular programs run right under Parallels at a store.

    Not quite ready for prime time yet.

  4. Eru Ithildur

    Eru Ithildur Forum Maven

    It would probably be fine. We use a bunch of computers with Parallels and as long as you don't use BETAs or do system-level changes much you should be just fine.
  5. Eru Ithildur

    Eru Ithildur Forum Maven

    PJK, just test the programs with a test key prior to buying.
  6. mmischke

    mmischke Hunter


    I dunno. Maybe I've just been lucky, but I'm just not seeing any of the problems that are being reported in these forums. With 3 GB, you seem to have plenty of memory. Are you starving either side of the house by allocating too much or too little RAM to Parallels? This seems to be a very common situation. Use XP's Task Manager and OS X's Activity Monitor to find out. Look for excessive paging in either OS. Since OS X and the XP VM share a single physical drive, too much paging in either OS will bring everything to a crawl.

    Did you perform a clean XP install under Parallels or did you clone a physical machine w/Transporter? If it was a Transporter import, the first thing I'd try is a clean installation.
  7. David5000

    David5000 Pro

    For us Mac users who are Windows neophytes, could you give us some kind of benchmark for what constitutes excessive paging? I can see the numbers of "Reads in" and "Writes out" in Activity Monitor but have no idea what these mean.

    Also, where is XP's Task Manager? I used Search in the Start menu (XP Pro SP2) but couldn't find anything.

    Thank you,

  8. drval

    drval Pro

    Use Paralles/Actions/Send Keys/CTL-ALT-DEL
  9. mmischke

    mmischke Hunter

    Sure thing. The best tool for diagnosing paging is the human ear. The next best tool is the drive activity light (physical and/or virtual). OSs have a set amount of physical RAM and they simulate additional RAM as virtual memory using large files on the hard disk (this has nothing to do with OS virtualization, BTW). Windows calls these files paging files (C:\pagefile.sys) and OS X & Linux call them swapfiles. OSs move a lot of data around as they service running apps and their own internal processes. They prefer to do this in physical RAM, which is about 1000x faster than virtual memory, but if they become starved for RAM they have no choice but to dip into the virtual memory pool. That means the hard drive starts chugging away and performance plummets. Paging (host or guest) will manifest itself audibly and persistently, as well as visibly if you have a drive light. If you're not a Windows geek or a general OS 'under-the-hood' guy, Task Manager/Activity Monitor-based diagnostics might be more confusing than enlightening. Stick with sound & sight at first.

    Many Mac users have little or no experience with Windows, but are in the position of needing to run one or three Windows apps. While I prefer to avoid rules of thumb for scenarios as complex as running one OS under another via virtualizatiuon, I'll toss a few out there in the hope that some folks might benefit (I'm primarily targeting Mac users who want to run XP under Parallels).

    1) Multi-core CPUs make for a much nicer virtualization experience than single-core CPUs.

    2) Think 2 GB of physical RAM, minimum, and don't be stingy with your virtualized OS. Windows wants 512 - 768 MB even for moderate workloads. Having said that, a well-cared-for XP setup can handle hardcore software development tasks with only 1 GB. I see a lot of folks here running Parallels on Macs with 1 GB RAM and allocating 256 MB to XP. That's just not going to work out very well in most cases. RAM, RAM, RAM. And did I mention RAM? :) Both XP and OS X have an insatiable appetite for it. If they're both on the same hard drive and you starve one, you starve them both, since they both become I/O-bound.

    3) Stick with the basics. Use virtualized XP to run those special apps you need to run. Avoid Webcams, Coherence, drag & drop, etc. if you experience problems with any of them. Virtualization has been a key aspect of my professional life for 5-6 years and I believe that less is more. The newer features will stabilize over time and I applaud Parallels for introducing several of them, but for now, venture there only if you're prepared to deal with potential problems.

    BTW - my description glosses over many details about how demand-paged OSs (most modern OSs that we encounter) deal with memory, but hopefully it illustrates how OS performance can plummet when it doesn't have enough physical RAM.

    Given that many (most?) Intel Macs are dual-core, my advice to Mac folks is to boost your RAM to 2 GB and give XP 768 MB to start. You can then try lowering or upping that number until you hit a sweet spot for your own scenario. It also helps a lot to disable the XP 'glitz' (Control Panel -> System -> Advanced tab -> Performance button). Configure it for best performance).
  10. dangcookie

    dangcookie Member

    I'd like some general advice as to why not to use Coherence. Several statements above mention that Coherence is not the most stable way to go with Parallels. Why? And does it use more memory? Or with Version 3 has Coherence been cleaned up? Any advice is appreciated!

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