Mac Pro as a VMware virtualization workstation

Question

Hello all,
I've used my Mac Pro quite heavily for virtualization-related tasks, from running a couple of Windows (XP and 7) VMs for various apps I need to support on both platforms.  My virtualization needs are taking a steep increase.  While I'd love a beautiful 12-core monster, can't afford that...yet :-(.  Thinking instead about maxing this one out.  The CPUs are as good as possible I believe, Xeon X5365'[email protected] x8.  Want to upgrade RAM from 12GB to 32GB, add an Apple RAID card (unless someone has a better suggestion?), 4x Seagate Constellation 2TB SAS drives in RAID-0 (I want maximum performance possible, multiple VMs, 12-14 at once, will cause very high I/O usage, capacity and performance are most important to me), I'll backup necessary stuff external via iSCSI SAN.  Does anyone have a better plan for achieving max performance from this workhorse?  Any opinions welcomed!  Thanks.

Answer 1

Whoa!  That sounds like it could be incredibly expensive!  Let's start with the easy stuff! Activity Monitor and the Windows Task Manager inside the virtual machines can inform you of RAM usage and help you decide if that's the better first step.  If you're maxing out your RAM usage within the VMs, they will start using the hard drive(s) as RAM.  That's incredibly slow, because hard drives are a lot slower than RAM. You should also check the settings for RAM allocation for your individual VMs using your virtualization client (VMWare) to make sure they can access as much RAM as the system will comfortably allow.  12 VMs running simultaneously on 12 GB of RAM means that each system will be allowed less than 1 GB.  That's not much for Windows 7.  You also need to remember that your host OS needs RAM, too.  If your RAM allocation settings are less than ideal, adjusting them can provide a tremendous gain in performance for FREE!
I predict RAM will be of greatest benefit to you, and it's cheap, so it's a good place to start. Increasing your RAM alone might give you the performance edge you want without a storage upgrade.  Do keep in mind that adding additional RAM to the system will require you to revisit those allocation settings to make any difference in performance of the VMs (assuming they hit their memory ceilings, which seems quite likely). If you have 32 GB, 14 VMs can use over 2 GB simultaneously and leave plenty of room for the host OS.
As far as storage goes, I'm hearing that the Apple RAID cards are over-priced and the fact that they are internal could make things far more difficult for you.  I'd recommend trying SSD, but the cost/benefit of that will depend on your budget and spatial requirements of your VMs.  I'm also not sure if they can match the reliability of the server-grade rotating storage you have in mind, but theoretically, neither can the hard drive(s) you already have in the machine.
I'd also check out an external solution rather than an internal one:
http://eshop.macsales.com/MyOWC/Upgrades.cfm?sort=pop&model=264&type=Hard+Drive+ Controller
There are many different options for hard drive controllers and you can read reviews for nearly all of them. They're not all equal and there is something different for every budget.
External storage is probably the best solution for you because it maintains the functionality of the internal drives you already have while you migrate to the new system.  In the future, you could continue to use those drives for archival and backup.  Of course, you could always simply migrate a portion of the VMs outside the machine into the external system and use both internal and external systems simultaneously.  When you decide to upgrade the computer, you'll be able to move the card and enclosure to a new machine more easily.
REMEMBER: If you're running a bunch of VMs with high demand for disk I/O, spreading the load over a greater number of hard drives can reduce the queue length for each individual drive and reduce latency. Try using different disks for different VMs.
This my plan of attack for you:
optimize your RAM allocations
check your performance
upgrade your RAM
optimize your RAM allocations again
check your performance
run heavy operations and check disk usage in Activity Monitor
if disk usage in Activity Monitor stays pegged at max of drive capability and you have available drive bays, add an aditional internal hard drive, or two, or three.
migrate some of the VMs to the new hard drive(s) and run them from their new locations to test performance again
if you're still not happy, consider RAID and have yourself a good cry when you see the price-tag
I predict you'll be overjoyed by the time you reach step 5.  Just keep in mind, hard drives fail!  Redundancy is important and off-site backup can be a life-saver in case of disaster.
Let me know if this helps! Don't forget, mark this reply as helpful if it helped or correct if I nailed it.