WorldMark 4300 Terminal Server

Provide continuous computing with NCR's Terminal Server solution

NCR's WorldMark 4300 Terminal Server lets IS departments provide continuouscomputing through thin-client terminals that access a fault-tolerant centralstorage system. The combination of the WorldMark 4300's hardware; Windows NTServer 4.0, Terminal Server Edition; and NCR's LifeKeeper 2.0 clusteringcomponent brings high availability and thin-client computing to the enterpriseforefront. I tested a WorldMark 4300 in the Windows NT Magazine Lab tosee if NCR's solution successfully implements thin-client technology.

And in This Cabinet
The WorldMark 4300's 77" cabinet houses two 4-way servers and an NCR6257 disk array subsystem. The two servers are identical in both size and shape.Each server contains four 200MHz Pentium Pro processors, 1GB of memory, a 4.3GBhard disk, and one SMC 10/100 Ethernet adapter. Each server has SCSI connectionsto the disk array made up of ten 4GB hard disks. Terminal Server and LifeKeeperare installed on both systems, but you must configure them.

The two servers connect to an Apex keyboard/video/mouse switch (KVM switch)that is rack-mounted inside the WorldMark 4300's cabinet. You connect a monitor,keyboard, and mouse to the KVM switch. This configuration lets you togglebetween each server's display using the Print Scrn key and lets you use thearrow keys to select each server from a pop-up menu.

New Life with LifeKeeper 2.0
One benefit of the NCR Terminal Server solution is that it brings LifeKeeperto the Terminal Server community. You can use LifeKeeper to achieve the bestapplication availability possible. LifeKeeper lets you depend on maximumapplication availability during scheduled or unscheduled downtime.

An enhancement to LifeKeeper, known as Cascading Recovery, lets anapplication endure against multiple failures within a cluster. Thus, anapplication simply cascades over to another system if one system fails. For areview of LifeKeeper, see "Clustering Software for Your Network," July1998. For more information about clustering solutions and LifeKeeper, see MarkSmith, "NT Clustering Solutions Are Here," June 1998.

LifeKeeper provides failover capabilities for as many as 16 servers percluster. This functionality results in higher availability than most NTsolutions. LifeKeeper's robust fault-tolerance features provide failover supportfor the entire server rather than support for only front-end or back-endapplications.

LifeKeeper lets users define three components: protected alias host namesvia its LAN Manager recovery kit, protected IP addresses for continuous accessvia NCR's TCP/IP recovery kit, and continuous access to volumes forfault-tolerant storage. You can configure these components into a protectedresource hierarchy for each logical user group and achieve logical loadbalancing, to match users to specific Terminal Server hosts. Logical loadbalancing is different from capacity load balancing, in which users log on andload balancing software provides access via the least busy server.

When a server configured with LifeKeeper goes down, resources move to adifferent server in the cluster. This migration lets each Terminal Server systemprovide primary access and fault tolerance in the event of a malfunction. Forexample, you might have two Terminal Server systems providing thin-client accessto two departments. The first department has light users running smaller,code-efficient programs and applications that don't require much memory. Thesecond department has power users running CPU-intensive applications thatrequire more memory and have several applications running at the same time.Users from each department are on separate servers. LifeKeeper exists on bothTerminal Server systems, and each user group has a tailored resource hierarchy.If one of the Terminal Server systems encounters a failure, LifeKeeper detectsthe failure and transfers the hierarchy from the failed server to the runningserver. When users of the failed server reconnect via normal procedure, theyaccess the failed server's resources; however, the running server automaticallyservices its original users in addition to the failed server's users.

Choose Your Terminal Server Solution
The WorldMark 4300 can be configured with an impressive amount of additionalmemory, hard disks, and disk arrays for terabyte (TB) storage. The systemconfiguration NCR sent the Lab included two 4-way servers, but you need only addthe symmetric multiprocessing (SMP) system and 10GB of storage to eight nodesper cabinet. Each node can contain a minimum of 2 processors and a maximum of 32processors, and memory can be as little as 1GB per server (upgradeable to 4GBper server).

The architecture provides flexible configurations for a variety ofthin-client solutions. NCR provides tools such as SMP Manager (so you canprioritize the processor user) and Master Minder (which lets administratorsmanage applications via rules and thresholds). Neither of these programsprovides dynamic load balancing when both systems are online, but they canadjust when one server fails.

One Concern
My only concern about the WorldMark 4300 is that NCR encourages usinground-robin Domain Name System (DNS) or LifeKeeper's IP addressing rather thandynamic load balancing. Round-robin DNS comes native with Terminal Server, andLifeKeeper protected IP addressing is included in the base LifeKeeper software.But these provide only fault tolerance and not load balancing. You can install acopy of Citrix MetaFrame or Cubix Balanced Cluster Service on theWorldMark 4300, but I was disappointed that NCR didn't include either of themwith the system I received.

Marking the Path to Thin Clients
The WorldMark 4300 is a compelling solution for providing fault-tolerant, Terminal Server capabilities to clients. The system I tested includedeverything you look for in a Terminal Server solution. However,implementing 4-way servers raises the WorldMark 4300's price and results inusers placing their front-end and back-end applications on the sameserver. A server failure might reduce the performance of the surviving server.

Other solutions provide more flexibility using dual-processor systems,which you can flexibly configure. NCR is banking on its LifeKeeper solution, butin my opinion the company can enhance the base configuration by includingCubix's load-balancing solution, which offers a low-cost alternative to CitrixMetaFrame. The combination of LifeKeeper, Cubix Balanced Cluster Service,Terminal Server, and the WorldMark 4300 would form a resilient thin-clientcompetitor.