The IT industry is starting to migrate in a new 64bits world.
The slow movement will greatly accelerate as soon as new critical products will be releases in 64bits versions only.
Companies jumping on the bandwagon before others will have to great opportunity to offer significantly improved performances and successfully front today’s scalability requirements.
But benefits are proportional to complexity and the adoption can be an expensive challenge.
To simplify the process another IT phenomenon of the decade comes to help: server virtualization.
The problem
Moving to 64bits is risky and should be planned very carefully. Why?
First of all because it will be slow, and during the whole process, which could take up to 10 years to complete, companies will have to handle mixed environments, with 64bits operating systems already available but some mission critical applications still in 32bits.
It’s we see, even on a smaller scale, every time we deploy a new operating system: benefits from new technology enhancements are unreachable just because one business application is not supported in the new platform. And CIOs have to wait years before starting to update infrastructures.
In the same fashion embracing 64bits technology and its benefits could take years, until all applications driving our business are not ported and proven to be reliable on the new architecture.
The wait in this case could be much longer than waiting an application being ported from Windows NT 4.0 to 2000, and could cost much more money.
A second problem is related with hardware population: deciding to approach 64bits early in the industry conversion means having 2 different architectures to choose, buy, manage.
But most of all it means having useless hardware as soon as applications are ported.
Something you cannot avoid
Given so much issues it’s easy to think 64bits migration is something to avoid until it will be a de facto standard. But even deciding to postpone, it’s a step we could be forced to do sooner than expected.
One after another biggest vendors will start offering their products just in 64bits edition since the new architecture will be able to provide new degrees of scalability and performances, long required by customers.
Microsoft is the first company making this step, announcing its intention to develop several products in 64bits only, including the popular Exchange mail server, the new Windows 2003 Compute Cluster edition and one edition of its upcoming Windows codename Longhorn.
A complete switch off of 32bits production is expected somewhere around 2010.
Meanwhile Microsoft is already offering both versions for several critical products, like Windows XP and 2003, SQL Server 2005, Visual Studio 2005.
The giant software maker is not alone: many other vendors, including market leaders like Apple, IBM, Novell, Oracle, Red Hat, Sun, are developing, or already offering, their products for new architecture, claiming up to 10x performances gain.
On the hardware side both AMD and Intel counts on a technology able to run concurrently and transparently 32 and 64bits code, and are selling just 64bits processors for servers, desktops and laptops.
Thanks to them the hardware side of the adoption will complete much earlier than the software one.
How virtualization can help
To simplify management of 32 and 64bits mixed infrastructure, during the whole migration process, server virtualization surely often appears the best approach.
At the time of writing no virtualization platform has been written for the new architecture, but many are able to run 64bits virtual machines, thanks to new CPUs capabilities mentioned above.
The market leader, VMware, is able to run 64bits guest OSes in all its products, including the new ESX Server 3.0, the upcoming Server 1.0, and popular Workstation 5.5.1, but has limitations on supported processors: following table will detail which one is supported.
| AMD | Intel |
| Opteron revision E or later | Intel EM64T VT-capable processors |
| Athlon 64 revision D or later | |
| Turion 64 revision E or later | |
| Sempron 64 revision D or later |
(note that there is no way to recognize revision of AMD CPUs until you test them, so VMware suggests contacting the vendor itself for help).
Xen 3.0 is also able to run a mixed virtual infrastructure, and Virtual Iron, now based on Xen, will be able too since its release 3.0, expected at the end of the year.
Microsoft will support 64bits hosts OSes within its Virtual Server 2005 R2 thanks to the upcoming Service Pack 1, but decided to wait its Windows Server Virtualization before permitting to run 64bits virtual machines.
And since Windows Server Virtualization in expected within two years, we can safely assume Microsoft technology is not a viable solution for 64bits early adopters.
Thanks to VMware, Xen, AMD, Intel and others that will come, deciding to adopt the next generation architecture can be smoother and cheaper than expected.
Depending on your business needs you could approach the migration with two opposite strategies.
The first one consists in moving existing 32bits applications in virtual machines, while modernizing hardware population and testing new products on new servers.
In this way virtual machines will act as hot-standby proven solutions when we’ll decide to adopt 64bits applications, without introducing significant efforts in maintaining two different machine sets.
And as side benefit the dismantling of 32bits servers will proceed much faster.
This strategy is the most aggressive and is probably better for companies trying to gain benefits from new architecture as soon as possible.
The opposite approach consists in maintaining existing 32bits hardware population and carefully introducing 64bits new applications just in virtual machines, where new products can be tested and verified.
The huge missing of 64bits drivers for many real devices makes virtual environments a more stable platform where to work.
This strategy fits better in mission-critical scenarios, but it’s likely to force virtualization adoption: if at a certain point the company decides to move back applications on real hardware the whole process could be painful.
For this reason it’s better go this path only if server consolidation was already estimated.
In many cases some companies will find useful adopt both strategies at the same time, depending on departments.
Whatever direction you’ll adopt at today the only possibility is buying a 64bits physical host where to install a 32bits operating system.
Luckily this won’t hurt because at the right moment, when virtualization firms will be ready to offer 64bits solutions, we’ll be able to change the host OS and the virtualization platform without rebuilding existing virtual machines.
And thanks to high availability solutions the operation will occur even without business interruption.
This article originally appeared on SearchServerVirtualization.