VMWare Pre-Allocated vs. Growable, which is faster?

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In an effort to increase speed in my Vmware setup, I was thinking about converting a Windows XP Guest 32 bit I have from growable to pre-allocated, I'm currently running VMWare Workstation 7 with Windows 7 64 bit as the host.

Specs:

Dual Core CPU, one allocated to guest 4GB of RAM, 2GB to guest HD max capacity is 500GB, 150GB allocated to guest (I have 300GB left and don't mind parting with the space, currently HD is 80GB and converting would obviously add another 70GB of space), HD that guest is running on is separate from Host OS

Either that or any other suggestions you have might be appreciated, thanks!

tekiegreg

Posted 2009-11-17T00:03:11.863

Reputation: 187

Answers

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Pre-Allocated space is always faster, as there are no background resizing operations and calculations that have to take place. Since you have a dual core CPU, you can also allow your guest to use both of them as well. Keep in mind though, once a VM is already created, it may become unstable if you change the number of CPU cores available. If you intend on using multiple CPU cores, I'd suggest configuring that when you initially create the VM.

John T

Posted 2009-11-17T00:03:11.863

Reputation: 149 037

Don't make your VM use multiple vCPUs unless you have an actual need to do so. There is more overhead even at idle with a >1vCPU VM. Also, about the "may become unstable" statement, this is a function of the guest OS. If you can add multiple CPUs to your guest OS, power on and have it work, then it'll work with VMware. On all modern Linux distributions this works flawlessly. I'm not 100% sure, but I bet if you're careful and add virtual cores but keep the virtual CPU at 1, Windows 7 and beyond will probably react OK too. – kbyrd – 2011-11-03T22:27:02.067

2Because of the way VMWare schedules VM access to processor resource, at times when the host is under any significant load (ie. it is running several VMs not just one) it is often better to give individual VMs only one vCPU. – David Spillett – 2009-11-17T00:15:54.037

Asked: 2009-11-17T00:03:11.863

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Active: 2016-02-12T09:23:11.577