OmniCluster Technologies' SlotServer

Note: this review is specific to the SlotServer 1000. OmniCluster's SlotServer 3000 has additional features and memory.

Wouldn't it be nice to have a complete, multiplatform network at your fingertips—one that fits right on your desk? That may not be the first item on everyone's wish list, but as a company that creates solutions for integrating different operating systems, it certainly ranked high on ours.

The biggest limiting factor to accomplishing this was obviously space, but with the help of OmniCluster Technologies, our dream became a reality. We first met OmniCluster at LinuxWorld 2001 in San Francisco, where they were demonstrating what looked like some type of network expansion board, but turned out to be a complete Linux blade server on a PCI card.

The SlotServer is a half-length industry standard PCI card that contains a fully compatible x86-based server blade with two network adapters. The standard bracket provides an integrated 100Mbps network interface. A second “Modular Network” is also provided as a peer network connection between the host system and each card. This network adapter is essentially two Gigabit Ethernet adapters set back to back in the same integrated circuit. One of these adapters is connected to the PCI bus of the SlotServer processor and the other connects to the PCI bottom-edge connector and hence to the “host” system. Multiple peer modular networks can then form a high-speed local private network with the host machine. This high-speed connection allows each SlotServer to operate diskless Windows or Linux from a “virtual partition” of the host machine's filesystem. This permits a RAID filesystem to be shared by many SlotServers and enables a provided utility, called Virtual Disk Manager, to create, replicate, remove and associate operating system images for all the SlotServers in a system. The SlotServer kit even includes one sample OS image.

The SlotServer can be loaded with Windows 2000, NT, XP, Linux and FreeBSD operating system environments and can run any application supported by those operating systems. It fits into any standard PCI slot, allowing you to have complex server clusters and multiple operating systems within a single PC base. The minimum of two network ports per SlotServer permits processing information in-line to or from the host.

We had previously looked at other blade servers from various vendors, but they were considerably more expensive and required an additional proprietary chassis, bumping the cost up even more. So, we decided to give the SlotServer a try.

We obtained our first SlotServer for use in our support organization. Our products run on Windows and provide file-sharing capabilities with any operating system that uses NFS (network filesystem), including UNIX or Linux, so we get support calls involving a wide range of operating systems. With the different variations of UNIX and Linux available, we would require a large number of servers in-house if we did support using traditional methods. The ability to use SlotServers to run these operating systems has allowed us to support them by using only a couple of mini-tower-based host systems. We have saved countless hours in building and rebuilding systems to different operating systems or specific versions of an operating system, enabling us to test and resolve issues more quickly for our customers.

The SlotServer provides the same benefits of multiple servers and operating systems within one system for our developers. Our products run on and are developed on the Windows operating system. However, since the products are used to share files between Windows and other operating systems, a minimum of two machines are needed for even a cursory test. Using the installed SlotServer, the developers have a complete test environment consisting of two different operating systems within a single machine. This allows them to perform functionality tests efficiently without needing external resources. It's also very helpful when testing precertified, unstable code. If a blue screen occurs on the SlotServer, their host machine will not be affected.

The SlotServer has also proven to be very beneficial for us at tradeshows. They're lightweight and easy to ship—we used to spend a small fortune just shipping the number of various machines we needed to demonstrate our products. With the ability to configure different operating systems on each SlotServer within one mini-tower system, we are able to demonstrate all of our products at a tradeshow using one mini-tower and two laptops.

We can also easily change our server configuration, for example, from Red Hat to SuSE or any of the many other operating systems supported on the SlotServer. If we are demonstrating our DiskAccess NFS client or X-Win32 X server with Red Hat NFS server loaded on the SlotServer, and someone wants to see our products working with a SuSE NFS server, we can quickly comply with their request. The SlotServer allows you to boot up in different operating system images by way of OmniCluster's host-resident Virtual Disk Manager (VDM). We simply assign the SuSE boot image to the SlotServer and reboot it via VDM without affecting the host system or any of the other SlotServers installed within the host system. One operating system and its associated applications can be exchanged in a minute or so. With this ease of configuration, we can demonstrate our products within another company's server by simply installing the SlotServer in an available PCI slot and powering up their system.

While our use of the SlotServers has advantages from which others could benefit, the different applications that can share a mutual benefit with these devices is tremendous. Some of the more mainstream uses for the SlotServers include front-end servers for highly available web clusters, generic application mirroring for automatic failover and even a dedicated firewall solution (Check Point) that runs inside mission-critical servers. The use of industry-standard PCI as the SlotServers host interface means that blade systems made with SlotServer are not proprietary. We can use any available PCI system as the host and any of thousands of PCI peripheral cards can be mixed in our configurations as necessary.

Note: this review is specific to the SlotServer 1000. OmniCluster's SlotServer 3000 has additional features and memory. For additional information on both of these products, please visit

Product Information/The Good/The Bad


Linda Hypes is sales and marketing director at Shaffer Solutions for the AccessNFS Product Suite.