One of the questions that is asked commonly in-house is what does it mean when we “see” Enterprise Vault “Going 64 bit”? Well to start with a recap on processor / memory address architecture will remind us that in a 32 bit OS, each process gets 4 Gb of virtual address space. Of that 2 Gb is for the user mode portion, and 2 Gb is for the kernel (ie Operating System). This can be adjusted in general with the /3Gb switch – though it’s not recommended on an Enterprise Vault server. With that switch it means that the process, or user mode portion is 3 Gb, and the kernel mode portion is 1 Gb. So that’s each process that gets this virtual space, regardless of physical memory. Another thing to consider is that 32 bit Operating Systems can’t “see” (or put another way they can’t “address”) more than 4 Gb of physical RAM. So if you 6 Gb of RAM in your nice Windows 7 x86 system, the Operating System will only say 3 Gb of that. The same is true of server Operating Systems.
“Going 64 bit” means that these limits are blown completely out of the water.
HOWEVER… Enterprise Vault is not turning 64 bit overnight. With the upcoming release of Enterprise Vault 10, the Indexing component will be 64 Bit. The rest will remain 32 bit. It’s a slow and gradual process for Enterprise Vault to move over to 64 bit.
Whilst this doesn’t mean all our cares in the world will be gone with Enterprise Vault 10, it will be a very strong step in the right direction. Enterprise Vault 10 will also require Windows 2008 R2 x64 underneath it for installation, it’ll make the Compatibility Guide so much nice/simpler to read!
Have a read of this for some background information : http://www.brianmadden.com/blogs/brianmadden/archive/2004/02/19/the-4gb-windows-memory-limit-what-does-it-really-mean.aspx