Modern Middle Manager
Primarily my musings on the practical application of technology and management principles at a financial services company.

Monday, December 02, 2002  

Server consolidation is about saving money. Thanks to the condition known as DLL Hell (for those of us using Microsoft products -- another discussion for another time), it is almost impossible to run more than one any major application on a server. So what to do? Dedicate one server per application? Although robust, it's definitely expensive. There is a technology that make server consolidation cheaper and easier to implement than ever, while preserving IS departments from DLL conflicts -- virtualized servers. The concept of a virtual server is as old as the mainframe; several "virtual servers" that act like independent servers running on their own hardware actually run on a single physical server with the aid of a program or specialized operating system that doles out resources like memory and hard disk space to each virtual server.

At my company we use VMWare's GSX server running on dual-processor Dell servers. GSX server is an application running on top of either Windows 2000 or Linux that manages the virtual servers. With this arrangement we've been able to get 2-4 virtual servers on each piece of real hardware. The best servers to virtualize initially are those that are not processing and RAM intensive. In our case, that meant some web servers, Sharepoint Portal Server, development servers, Windows 2000 domain controllers, FTP servers, file and print servers. Cost savings come quickly. Here's a typical scenario (server prices are from when we bought them):

Four dual-processor servers at $7K each (2xPentium III CPU's, 4GB RAM, 72GB Ultra-160 SCSI RAID 5 hard drive space) = $28K.
One dual-processor server at $7K plus a copy of VMWare's GSX server at $3K = $10K.
Assume the same cost for application and OS software licenses.
Cost savings are $18K, or 64%.

What about CPU, RAM or hard disk-intensive applications like Exchange or SQL? Well, we've been able to migrate our SQL server and Exchange 5.5 server (the latter by breaking it into two). We also had to use a dual-processor P4 Xeon server with 6GB RAM. It did the trick -- our SQL 7 server with our imaging, CRM, and intranet-based apps servicing 100 users runs very well. Our Outlook users likewise have no complaints. Another tack we took was to migrate the intensive I/O for SQL database devices and the Exchange information stores to a clustered Network Appliance F820 device. That speeded up I/O access considerably compared to GSX's virtualized hard disks. Next year we expect to explore VMWare's ESX server, which is a specialized OS rather than an application running on an existing OS. It's licensed on a per-CPU basis so it may not have the same kinds of cost savings GSX server does, but performance is supposed to be better.

Tomorrow I will explore some more benefits of this arrangement in the area of disaster recovery.

posted by Henry Jenkins | 12/02/2002 09:24:00 PM

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