RemoteServ/IS

When we began evaluating clustering solutions for this issue, we received an unusual clustering solution from Cubix. Most clustering solutions fall into two categories for availability: software and hardware. Many of these solutions involve a dedicated server for failover protection or data mirroring. But Cubix creates a virtual cluster within a Citrix WinFrame environment.

This virtual solution uses one or more loosely coupled servers functioning as one system and places them in between your network and remote user. A WinFrame Windows NT server lets multiple graphical terminals, workstations, or laptops run applications from one virtual server. This cluster acts as a network buffer to load balance network applications and provide fault tolerance. (For more information on Citrix WinFrame, see "Citrix WinFrame 1.6 Beta," May 1996.)

Although Cubix's clustering solution doesn't follow the pack, it is worthy of review. This solution expands on the remote-access concept with a combination hardware and software solution that also works well on local networks.

Under the Hood
The hardware consists of RemoteServ/IS, which is an impressive rack-mounted microcomputer chassis. The chassis supports five to eight load-balanced processing subsystems depending on configuration choice. The software half of this dynamic duo is a package containing Citrix WinFrame, WorldDesk Server for NT, WorldDesk Manager, and WorldDesk NT Client.

The RemoteServ/IS comes preinstalled with Citrix WinFrame 1.6 on a single server and includes whatever hardware options you require. Options include multiple servers or workstations, type and size of hard disks, CD-ROM drives, RAM, and network connections. The software package includes WorldDesk Server and GlobalVision, an administrator's management application. World- Desk Client software comes in four versions: NT, Windows 95, DOS, and Windows 3.1x. The base package includes a three-year complete warranty. Support contracts are available after the initial warranty expires. Training is available from Cubix and is specifically tailored to the user. The user interface is identical to NT 3.51.

My initial impression was that Cubix had taken several applications servers, which usually reside on different machines, and consolidated them into a robust single chassis. Citrix WinFrame is an applications server that boasts speed, security, and scalability advantages in remote access communication. Citrix WinFrame uses a licensed NT kernel as the core operating system. WorldDesk Server builds on NT's Remote Access Service (RAS), scalability, and security, and adds load balancing and failover across the subsystems. WorldDesk NT Client manages the connection from the client workstation. You can use the RemoteServ/IS apart from the software as a general purpose Primary Domain Controller (PDC), Backup Domain Controller (BDC), file server, mail server, and Exchange server, all in one box.

The RemoteServ/IS chassis features a backplane architecture that supports floppy and CD-ROM drives and up to eight ISA or PCI card slot configurations. Each card is a 200MHz Pentium with a maximum of 128MB of RAM, SCSI connections, and a built-in 10/100Mbps Ethernet port. The backplane architecture is connected to the Integral Multiplexor, which supports single-point I/O for video, mouse, keyboard, and floppy drive support, and it can support hot swapping of individual PC cards. Additional hardware options for processors and RAM are available from Cubix.

The chassis features two redundant load-sharing power supplies, each with its own power cord so you can draw power from different electrical grids. The chassis also contains nine disk bays. Our testing model was installed with one 3.5" floppy drive, a CD-ROM drive, two 1.2GB hard disks, and three 601MB hard disks.

The chassis has an Intelligent Environmental Sensor (IES) integrated into a printed circuit board that monitors environmental conditions such as temperature, voltage, fan rotation, fuses, and hardware resets for the entire assembly. The Front Panel Control allows easy computer selection, independent processor reset, port diagnostics, and Console LOCK, so no one can change settings unless authorized to do so.

The Citrix WinFrame operating system is essentially the NT 3.51 kernel modified to support multiuser access for local or remote users. Remote access (modem or ISDN) under Citrix WinFrame simply extends the company's LAN to the user's remote site.

WinFrame uses Intelligent Console Architecture (ICA) as its underlying protocol. ICA lets workstations access NT applications over a network by letting one NT server handle several desktop users. ICA is designed for remote dial-in networks, but it has expanded to encompass LAN links. ICA operates over TCP/IP by transmitting a minimum amount of information over the network. ICA features data compression, speeding up remote application execution. When you run an NT application with ICA, you keep the resource utilization on the server using server-side CPU, memory, and disk storage. The user sees little difference between a locally running application and a remote application.

Cubix WorldDesk Server is the engine that creates clusters, or collections of servers, that work independently but interact to perform load balancing and provide fault tolerance during ordinary operation, resulting in a high availability application server. Clients see only one point of dial-in or dial-out access; the next available port is always automatically connected. If the load becomes too large while remote applications are running, you can add Citrix WinFrame servers dynamically to increase processor and I/O resources to handle the load. If any servers in a cluster fail, the load is rebalanced and the services continue without administrator intervention.

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