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.
The Test Drive
For testing purposes, we received a RemoteServ/IS preconfigured with Citrix WinFrame 1.6, WorldDesk Server 1.32, WorldDesk Manager 1.32, and WorldDesk Client 1.32 for NT. (Client software is also available for DOS, Win3.1x, and Win95.) Cubix's tech support was outstanding--one phone call and I was talking to Product Manager Gary Lyon. Gary quickly and logically stepped me through the operation and configuration.
With WorldDesk Manager, I configured a virtual cluster from two Citrix WinFrame servers, as Screen 1 shows. When prompted, I selected a Master Server within the cluster to handle the administrative overhead for the cluster. If the Master Server fails, the remaining servers elect a new Master, all transparent to the user (much like when a BDC is promoted to a PDC). In my testing, the role of Master Server simply alternated between the two available servers.
Load balancing and failover testing were complete and effortless. My initial installation software had an outdated mouse driver for the Integral Multiplexor. The Master Server kept locking up on the mouse and keyboard. Cubix is aware of the driver problem and supplied the updated drivers within 24 hours.
After I installed the new driver, I did not experience system lockups. RemoteServ/IS let me isolate the PC board and reset the server. The second Citrix WinFrame server picked up the role of Master Server, and the remote application service continued to operate.
With RemoteServ/IS, I could power up or power down any subsystem, including multimodem, multiport, and ISDN adapter cards. After the original server was back online, I cut power and reset the remaining server. The roles reverted. The internal switching between the two servers was transparent to the workstations and me.
WorldDesk Manager contains powerful and simple tools for application management. Several key features stood out during my review: For example, the administrator can set application configuration rules using IF/THEN Boolean algebra. Screen 2 shows the Use Rules radio button selected for where to run the program. This feature lets the administrator set parameters for whether an application will run locally or remotely. For example, I set a rule, "IF the application accessed is greater than 75KB, THEN run the application on the server." This statement means that if a program has a certain RAM requirement, the administrator can run the program from either the server or a remote location.
You can also use WorldDesk Manager to enhance security by selecting the domain or workgroup server that manages logon accounts to control authentication. This feature also means no extra logon procedures. I tested usernames and passwords to confirm the connection. I also set specific user time limitations by hours or days.
WorldDesk Server supports Data Encryption Standard (DES), the encryption algorithm that the National Institute of Standards and Technology (NIST) developed. Plus an administrator can monitor remote access sessions in several different options, produce graphic outputs, and manually adjust load balancing.
On The Road
The best software feature is the easy configuration of the WorldDesk Client software for remote access users. Cubix calls this feature the I Can Icon. Gary Lyon talked me through the procedure once, and then I had fun.
From the WorldDesk Server dialog box, I activated the Setup Configuration icon to start the WorldDesk Client Preconfiguration window shown in Screen 3. First, I designated applications for remote access. Settings include an icon label, network path, dial-in number, and working folder. Then I saved the information to the WorldDesk NT Client disk. With this disk, I was able to go to any workstation on the network and run setup.exe. (You can run this command from either the client disks or a network drive.) Presto! The workstation now had icons for the remote access applications installed on the desktop. I could double-click any of the icons to start a remote access session, and I could use the application as if it were running from the workstation.
I was surprised at the operation speed. I ran a graphics program to see how it affected packet transmission and speed. With the Network Statistics feature, I monitored the rise in packets transmitted and received. But even working with a large .bmp image, I saw no visible slowdown at the workstation.
The beauty of the remote access feature is evident for any multinational organization with employees around the world. For example, imagine a marketing manager traveling on the US East Coast. Suppose this manager needs access to the vendor database on the company server in Colorado. You can set up the application the marketing manager needs, save the configuration to a WorldDesk NT Client disk, and deliver the disk overnight. The manager runs a:\setup, plugs into any modem, and clicks the desired icon to start a remote access session.
To the marketing manager, the application runs as it does at the local workstation in Colorado. The end user will love this feature for its simplicity; the administrator will love it because no additional end-user training is required and it doesn't compromise security.
No Sunday Driver
One difficulty I had during my review of Cubix's clustering solution was wading through the documentation. Cubix admits the documents are not for the casual reader but are meant for technical reference. The two hardware manuals remind me of learning the thermo-dynamic characteristics of the third-stage compression blade assembly of a high bypass turbofan engine: highly technical! The System Administrator's Guide for WorldDesk is manageable if you're familiar with Citrix WinFrame. New users will prefer a more user-friendly installation and configuration guide, with plenty of screen shots. A picture is worth a thousand words.
The technical support from Gary Lyon and his staff was superb. Gary discussed and explained all the technical aspects of RemoteServ/IS and led me through the GUI for cluster configuration. His help more than made up for the user manuals. Excellent product technical information and white papers are available at the company's Web site. Overall, the RemoteServ/IS is a superb combination of hardware and software, a must for the network administrator seeking remote access functionality, with security and availability.*
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