Network Computing
Issue 33 - September 2002
Consolidation of Servers
By Peter Mok

Like most of the other organisations, our University is experiencing rapid growth in the use of IT at the time when reduction of supporting manpower continues. Seeking ways to optimise the effectiveness and efficiency of the available support work force is inevitably the only solution to the problem. Server consolidation on the operating system platforms, data storage and the services has therefore been adopted as one of our strategies to meet the challenge. Consolidation of servers in the CityU is divided into three parts, namely Central Unix-based application servers and storage, departmental Windows-based LAN servers and storage, and Central Web and FTP servers.

A. Consolidation of Central Unix-based Application Servers and Storage

Consolidation involves the establishment of Unix servers, each capable of being partitioned into virtual servers, to replace the old and smaller servers together with the use of central network storage system (mainly SAN which can efficiently handle large databases or files with large size) as the common storage instead of conventional direct attached storage for each individual machine. The advantages of this approach are much simpler management, more efficient operations, flexible data sharing, high data availability, and real time on-demand expansion of storage space, etc. All these lead to tremendous improvement on the availability and reliability of the central servers and data, and thus on the quality of the central services which are critical and essential to the University operations. The Consolidation began in 1999 and is now more or less completed.

At the moment we have four Sun Enterprise class servers configured with 23 domains (virtual machines) to provide support to the most critical services in the University. These cover systems for learning, teaching, communication, research, and administration. These large Enterprise servers are grouped and configured dynamically to enable load-balancing, clustering, high availability and fault-resilient capability.

The storage of all the central servers is provided by a large Network Storage System and a Tape Library backup system from EMC. The existing Storage Area Network (SAN) has 7-terabyte Storage capacity and can handle scheduled and unattended backup of all systems, LAN-lessly and server-lessly.

B. Consolidation of Windows-based Departmental LAN Servers and Storage

Our University has some 60+ departmental servers running a mixture of Windows NT 4.0 and Windows 2000 Server systems to support file services to staff in various departments. At present, each departmental server handles network service requests from only its own departmental staff PCs, and all data and software are served from individual local storage directly attached to it. Apart from the problems of replication of operating system, software, and patch updates to these departmental servers, to manage effectively such vast volume of data scattered among the 60+ servers has become a great challenge to the Computing Services Centre (CSC). To solve these problems, a few NT/Windows 2000 Server Clusters and a central network storage system (mainly NAS which handles very efficiently the sharing of small files or the I/O operations at file level) have been installed. In fact, with these facilities, our Windows users can enjoy the same quality services as those being offered to Unix users by the Unix server clusters and SAN.

Our Windows server clusters include Windows server farms from IBM and Dell while the NAS system is an EMC Celerra with four Data Movers and a total of 1.4 Terabytes storage. Starting this September, the existing 60+ departmental file servers will be gradually replaced by these Windows server clusters, and their data also migrated to NAS accordingly.

C. Central Servers for Hosting Web sites and providing FTP services

As you may probably know, more than 450 Web or FTP servers of various kinds have been set up and used in the University by various departments. Most of these servers are used to provide services to University users or the public accessed from within or outside the University. As server management is undoubtedly a complex and labour intensive task that demands high management and technical skills, perhaps this explains why a number of servers set up by users are often being hacked or infected with viruses.

Central Web Hosting and FTP Services are hence set up to provide a consolidated, fully monitored and managed environment for hosting departments' Web sites, project Web sites, or FTP sites. As highly reliable and secure central servers will be used to host these services, Web site owners or FTP service providers can then concentrate on the development of their contents without the need to worry about the server management or operational support of the servers. It also releases these owners from the burden of keeping the individual servers secure and managing them.

It is hoped that this centralised support arrangement can eradicate the levels of risk of having so many Web and FTP servers distributed around the campus with different security protections. The consolidated infrastructure to host these Web and FTP sites also leverages the economy of scale, thereby creating significant cost savings.

The Central Unix Web Hosting service has been in place for quite some time with the Sun E6000 system to support the departmental Web and Intranet applications. This will be upgraded to two domains of E10000 in the form of load-balanced set up to meet the demand of Unix based Web server hosting.

A Central Intel-based Web Hosting server farm with database support will also be set up and added to the hosting services. It consists of the following:

  1. Database server

    1. A cluster of 2 nodes running Windows 2000 Advanced server, MSCS Cluster, and SQLserver 2000 will be set up.
    2. Shared data storage of 4 x 36GB mirrored disks will be used.
    3. This cluster can be expanded to 4 nodes using the DataCenter approach.

  2. Web server

    1. Two nodes, each running Windows 2000 server and IIS server, will be set up for storing and maintaining all the Web pages
    2. All the nodes will be connected to the F5 Load Balancer for load distribution.
    3. In general, this set-up can be expanded to nth nodes depending on the needs.

Immediately after its release, over ten PC based Web sites have already been migrated to this Intel based new Web Server.

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