64 vs 32 bit hosts

[lumstar]

So I have been reading a bit about the featires of 32bit vs 64 bit hosts and am wondering if there is a definitive answer on which have better perfmroance. I am currently running a few instances of Ubuntu server 8.04 64-bit. I am wondering if I will see any performance benefits if I switch to 32-bit and enable paravirtualization. Anyone have any idea?

Thanks

Stephen

[Borja_Mari]

Hi,

AFAIK the differences between 32 and 64 bit operating systems running in physical hosts remains basically the same on the vmware virtual machines. For example a 64 bit operating system uses in a natively manner the host memory above 4 GB. But 32 bits OS doesn't.

IMHO i won't enable paravirtualization (VMI) on the virtual machines, because AFAIK VMWare will drop its support in the future. You have to think about the fact nowadays the paravirtualization is a feature in the recent CPU's. Then maybe the VMI isn't really needed.

Regards/Saludos,

Pablo

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[AndreTheGiant]

Note that 64 bit does not mean that the VM will run faster than 32 bit.

One big difference is in memory allocation, so if you need more than 3,5 GB for each process the 64 bit architecture is a better choice.

But with small VM, the 64 bit architecture has more overhead, so (in this cases) IMHO I prefer to use 32 bit VMs.

Andre

[golddiggie]

Also note that when talking about VMware products, especially ESX/ESXi, "host" is the physical server where ESX/ESXi is directly installed/running. The VM where your server OS sites, like Ubluntu, is a "Guest". It is important to keep this clear since when you start talking one or the other, we make certain assumptions about what your talking about. For ESX/ESXi 4, the "host" hardware has to be 64 bit (processor) in order for it to be installed and run. You can install whichever bit level OS on the guest/VM to perform the duties required.

As previously mentioned, if you don't need more than 3.5-4GB of memory available to the guest, then go with a 32 bit OS. If you need over 4GB, then you'll want/need to use a 64 bit OS.

VMware VCP4

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[mudha]

is there any doc where it lists difference in 32 and 64 bit?

[jkumhar75]

Hi Stephen,

The 64-bit OS of Guest is prefered based on the support for the memory requirement for the application which you are planning to install on the VM.If you have more memory requirment then go for the 64-bit OS else 32-bit OS will be a better option.

Jay

MCSE,VCP 310,VCP 410

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[RParker]

Well unlike the rest of the posters in this thread, I don't agree with the addage that 32-bits is for Less than 4GB of RAM, that is a farce.

It all depends on the support level of your APPS. If your apps can take advantage of 64-bit, then install 64-bit. 64-bit is FULLY backwards compatible with 32-bit apps, so why not simply run 64-bit?

Also there is a growing theory (which is inaccurate) that somehow 64-bit OS will provide NO benefit other than memory usage, this is ALSO a farce. 64-bit is more efficient at MANY things other than Memory, for one it is more responsive. It may not be faster, but I find that at least 75% of time time you WILL notice a difference, and while the overall performance may not yield more productivity, it won't feel as draggy either.

My vote is to install 64-bit EVERY where you can. Forget 32-bit 64-bit is the future.

[AntonVZhbankov]

+100500 to RParker

---

MCSA, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[Borja_Mari]

Hi,

yep Anton, is a good post from RParker :smileywink:

I think basically the same about 32 bit vs 64 bits :smileyhappy:

Regards/Saludos,

Pablo

Please consider awarding any helpful answer. Thanks!! - Por favor considera premiar las respuestas útiles. ¡¡Muchas gracias!!

Virtually noob blog

[lumstar]

Hey Guys,

Thanks for the responses. So my main question is wehther the performance of a 64-bit guest is better or worse than that of a 32-bit guest on ESXI 4. Regardless on their performance on bar metal, I am wondering if ESXI handles one better than the other. I was specifically wondering due to the existence of VMI for 32-bit guests.

Thanks,

Stephen