Startups give virtualization new spin

Two startups debuted last month, together giving virtualization a new twist to help create large systems using multiple x86 servers. 3Leaf Systems is designing ASICs as part of its approach, while ScaleMP Inc. creates the links via software alone.

Hosting multiple OS on a single server is the focus for most virtualization products. The startups flip that notion on its head to stretch a single OS across as many as 16 servers, in effect creating a powerful symmetric multiprocessing system out of low-cost PC server motherboards.

Cache-coherent links3Leaf has licensed Intel Corp.'s QuickPath Interconnect bus as one ingredient in an ASIC that creates cache-coherent links between servers. The architectural design for the chip may not be available until 2010. Plans also include a version of the ASIC using AMD's HyperTransport.

Both 90nm ASICs will essentially look like another processor on a server motherboard but consume only 15W. They will establish cache-coherent links to other boards using generic networking blocks that can mimic a 10Gbit/s Ethernet or 20Gbit/s Infiniband connection.

"Our chip basically extends the coherency domain from a single server to a set of servers," said Bob Quinn, founder and chief technologist of 3Leaf. "The OS is protected from seeing the variety of physical servers via our distributed hypervisor."

The extended domain can embrace up to 64,000 servers. One Linux or Windows Server OS image can span up to 16 systems and a terabyte of memory. The company is planning a 2G chip that can put 256Tbytes of RAM under one OS.

Users will be able to write policies that set the minimum and maximum hardware resources an application can access.

3Leaf is talking with chip partners to make its ASICs under license. To date, it has raised $32.5 million from investors. The startup has given about a dozen beta users a version of its technology that virtualizes just the I/O. It is delivered as software running on an x86-based appliance with no special hardware. The appliance acts as an I/O gateway between a bank of servers and network and storage switches, increasing the utilization rate of network links and redundant servers.

For its part, ScaleMP can link a similar group of up to 16 servers and a terabyte of memory to make it look like a single system to one copy of a Linux OS. The startup uses software that plugs into each motherboard via a 32Mbyte USB drive.

3Lead chip creates third tier of coherency in x86 servers. Links to two Opteron processors and Infiniband or 10GbE.

The code creates virtual machine monitors for the systems, inventories their hardware resources and launches a hypervisor to control them. It then creates appropriate BIOS software that describes the resulting computer to a Linux OS.

The startup said its approach delivers performance similar to or better than that of single boards with as many cores. For example, two Intel motherboards with two dual-core processors on each one can outperform—by as much as 60 percent—a single board using an AMD four-core Barcelona CPU, ScaleMP claims.

The approach uses as many as 15 techniques to maintain memory coherency between boards. It typically uses 20Gbit/s Infiniband links.

"Our technology is interconnect-agnostic, but people tend to use Infiniband as the lowest-latency and highest-bandwidth approach," said ScaleMP CEO Shai Fultheim.

- Rick Merritt
EE Times