VMWare Fusion 4 and Multiple Virtual Machines

Discussion in 'Apple' started by W, Mar 31, 2012.

  1. W

    W Guest

    Does VMWare Fusion 4 running under OS X Lion finally address the performance
    problems that people were having running more than one virtual machine?

    I do realize that there are I/O bottlenecks to overcome in a situation where
    you have two or three Windows virtual machines running under OS X. Assume
    for now that you run the virtual machines on something like a Thunderbolt IO
    RAID box and that disk IO is not a bottleneck to the configuration. Will
    VMWare 4 allow such a configuration to run well?
    W, Mar 31, 2012
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  2. W

    Guest Guest

    add more memory.
    Guest, Mar 31, 2012
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  3. W

    W Guest

    Sure, assume a minimum of 8GB.

    But people using VMWare Fusion 3 under Snow Leopard were complaining of
    performance issues with multiple virtual machines, even with fast disk and 8
    GB of memory.
    W, Apr 1, 2012
  4. The hard disc is one of the lesser bottlenecks - although a faster hard
    disc should make virtual memory better, but even then the difference won't
    really be noticeable.

    The bigger problem for running multiple virtual machines is the fact that
    there's only one CPU, one set of RAM, one (possibly two) graphics chips,
    one network / Internet connection, etc.

    Even if you have a quad-codre CPU and VMWare (or Parallels) has been
    optimised to use them efficiently (e.g. perhaps one virtual machine per
    core), running three virtual machines and Mac OS X will always run slower
    than running just one virtual machine and Mac OS X, and it will always be
    slower than using Boot Camp or a separate computer.

    In the "good ol' days", Apple and others produced PC-on-a-card solutions
    to plug into a spare slot inside your Mac which got around some of these
    problems. I don't think anyone still makes those these days though.

    Helpful Harry :eek:)
    Helpful Harry, Apr 1, 2012
  5. W

    W Guest

    How many cores does OS X Lion need to run optimized performance on its own?
    Assume just ordinary user applications and nothing CPU intensive running on
    that box. I assume one core for mouse and keyboard, shared to
    applications, and one dedicated to applications, would probably give a
    decent result? That leaves two cores available to use for VMWare.
    Maybe two virtual machines in that case, each restricted to a single core?

    It would be nice to have a Mac Mini with a 12 core processor. That would
    probably address your concern.
    W, Apr 1, 2012
  6. W

    Paul Sture Guest

    FWIW I had the same complaint with VMware Workstation 3 with both Windows
    7 and Linux hosts. Plenty of free memory didn't help. In my case VMware
    was thrashing its own pagefiles which it creates on behalf of clients,
    which weren't actually needed given the spare RAM I had.

    One tip for virtual machines, and I have had this verified by others, is
    to spread your files across physical disks where you can. If possible
    keep the client disk containers off the system disk.
    Paul Sture, Apr 1, 2012
  7. W

    Alan Browne Guest

    Did you allocate a lot of RAM to Windows? Under Fusion you configure
    each virtual machine to have x memory. The Mac can have oodles but you
    can choke each virtual machine by RAM allocation.

    Not sure about Linux, but I suspect it's much the same.
    On the right machine, sure. On an iMac with serial interfaces to
    outside disks, it's not that cut an dried.

    As JR would likely suggest, each virtual machine should have its own
    partition on the system disk rather than a container under OS X. That
    will increase speed.
    Alan Browne, Apr 1, 2012
  8. W

    Paul Sture Guest

    I allocated plenty more to the Windows client than VirtualBox needs to
    give adequate performance with the same client.
    Of course it depends on how fast the disks are. I suspect that
    performance is better with external Firewire drives than having
    everything sitting on the system disk.
    I'm not sure JR would suggest that. If you set things up so that the
    virtual guest can use the disks in raw mode, you are certainly taking out
    one emulation layer, but you are not addressing disk head contention, and
    may in fact make it worse.
    Paul Sture, Apr 2, 2012
  9. W

    Alan Browne Guest

    That would be optimal in a Mac Pro, but less so in iMac/Mac Mini/laptops
    that don't have a SATA/e-SATA connection to other disks.

    Perhaps with Thunderbolt (or USB 3 or FW 3200 - not availble yet) it
    would be fast enough.
    Alan Browne, Apr 3, 2012
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