Maximum memory for VMware guests?

Hi All

We are running VMware ESX 3i 3.5.0 158869 update 4 on Blade 460c's.

We'll have different application servers running on these boxes, some with more memory requirements than others. According to MS, the memory limits are;

Windows 2003 Standard x32: 4GB
Windows 2003 Enterprise x32: 64 GB

Windows 2003 Standard x64: 32 GB
Windows 2003 Enterprise x64: 1TB

http://msdn.microsoft.com/en-us/library/aa366778.aspx#physical_memory_limits_windows_server_2003

However, it states that limits over 4GB for 32 bit Windows assume PAE is enabled.

Is PAE enabled on VMware guests? I'm not even too sure what it is? :)....so basically, my question is do these limits apply to virtual servers, or are they for physical boxes only?
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Joe_BuddenAsked:
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thetmanvnConnect With a Mentor Commented:
Look at this  http://www.vmware.com/products/esxi/features.html


Mware ESX and VMware ESXi deliver unparalleled performance and scalability, enabling even the most resource intensive production applications to be virtualized.

    * Support for powerful server hardware. Take advantage of hardware systems with up to 64 physical CPU cores, 256 virtual CPUs, 1TB RAM, and up to hundreds of virtual machines on a single host to facilitate large-scale consolidation and disaster recovery projects.
    * Support for larger virtual machines. Configure virtual machines with as much as 255GB RAM.

So ESXi 3.5.0 support up to 1TB RAM on Physical Host, and each VMachines are 255GB. So you can add maximium 255GB RAM to VMWare.

Of course on VMWare guest is treated like a normal physical computer, so the Microsoft limits will apply to it too, but there is right bound for maximium RAM. It means when you install Win2k3 Ent x64 on Physical Computer with 1TB RAM, use can use all 1TB RAM, but if you install Win2k3 Ent x64 on VMWare ESXi 3.5.0 with 1TB RAM, you can assign and use maximium 255GB RAM.
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rindiConnect With a Mentor Commented:
The PAE is set in the boot.ini file of the windows OS, it has nothing to do with VmWare itself.
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Paul SolovyovskyConnect With a Mentor Senior IT AdvisorCommented:
Yes PAE is enabled on the guests.  Since the virtual machine emulate "real" hardware with a motherboard, bios, etc.... it would be the same as in a physical machine

There are advantages in VMWare in that it performs transparant page file sharing where ESX sees similar page file from multiple VMs and only keeps a single instance with pointers to any duplicates.  Your VMs also use the baloon driver in VMWare Tools allowing VMWare to better share memory between your VMs

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vmwarun - ArunCommented:
thetmanvn, you are wrong buddy.

ESX 3.5/3.5i can maximum support 32 Logical CPU Cores, 256 GB RAM per Host and VMs can have a max of 65532 MB RAM (64 GB - 4MB).

Check this for more info - http://www.vmware.com/pdf/vi3_35/esx_3/r35u2/vi3_35_25_u2_config_max.pdf

All the things which you have mentioned are supported by vSphere 4.0.
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vmwarun - ArunCommented:
In computing, Physical Address Extension (PAE) is a feature of x86 and x86-64 processors that enable the use of more than 4 gigabytes[1] of physical memory to be used in 32-bit systems, given appropriate operating system support. PAE is provided by Intel Pentium Pro and above CPUs (including all later Pentium-series processors except the 400 MHz bus versions of the Pentium M), as well as by some compatible processors such as the Athlon and later models from AMD.

More info - http://en.wikipedia.org/wiki/Physical_Address_Extension
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thetmanvnCommented:
@arunraju: Maybe you should re-check my link, it all about esxi 3.5.0 features.
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vmwarun - ArunCommented:
@thetmanvn - ESXi 3.50 has a 32 Bit Kernel.
Only from vSphere 4.0, is the VMKernel 64-Bit.
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