A growing number of companies are spoiling for a fight between the ARM and x64 architectures in the data centre. The latest one to enter the ring is ZT Systems, a maker of low-powered servers that has just launched its first ARM-based server.
If you ask Intel, the company will emphatically deny that there is a market for servers based on low-powered processors such as the Atom, and even Google has chimed in, saying that wimpy-cored servers are not necessarily good for hyperscale data centres because the parallelisation of workloads across these machines means delayed response time compared to wonking fast-thread hot boxes. The market will decide, and as the ARM architecture grows up with the quad-core Cortex-A15 processors and beyond, economics will play a major and deciding factor. If history is any guide, Intel had better buy Marvell, which bought Intel's Xscale ARM RISC chip biz back in 2006, or get Apple to use Atom processors in cell phones and tablets.
The R1801e server comes in a 1U server chassis and includes eight complete ARM-based server nodes, which the company calls a system on module, or SOM. The SOM board is based on STMicroelectronics' Spear1310 processor, a riff of the dual-core Cortex-A9 processor design from ARM Holdings using the ARMv7 32-bit cores. The Spear1310 processor has two ARM cores and is implemented in a 55 nanometer process geared for low-power chips. The cores spin at 600 MHz, which is not a particularly high clock speed to be sure. The Spear1310 can use these two cores asymmetrically (with each core getting a chunk of main memory allocated to it so it can run isolated from the other) or symmetrically (with each core sharing the main memory and effectively doubling the oomph of the processor). The cores had 32 KB or L1 data cache and 32 KB of L1 instruction cache, plus 512 KB of ECC-protected L2 cache that is shared by the two cores. The chip also includes 32 KB of BootROM and 32 KB of internal SRAM, and a multi-path memory controller that can support 800 MHz DDR2, 1.07 GHz DDR3, or 1.33 GHz DDR3 main memory, with a maximum capacity of 1 GB.
The Spear1310 chip has serial and external flash controllers and also has controllers to drive two Gigabit Ethernet ports, three 100 Mbit Ethernet ports, three PCI-Express 2.0 slots and one PCI slot, three 6 GB/sec SATA ports, and a bunch of USB ports. The chip also includes a video controller and a C3 cryptographic accelerator.
Each SOM in the ZT Systems ARM-based server includes one of these dual-core Spear1310 processors, 1 GB of 1.33 GHz DDR3 memory, and 1 GB of NAND flash memory. For storage, ZT Systems is chucking in an 80 GB solid state drive from Intel for each SOM. There's a CD drive as well that is shared by all of the SOMs in the 1U box. The ARM modules plug into a backplane that connects them to the shared CD/DVD drive as well as to a shared 250 watt power supply. The machine has no fans because it is cool enough to run without them. ZT Systems reckons the whole machine burns under 80 watts of power. (That's what the spec sheet says, and you can check here. I myself am skeptical of this claim.)
The ZT Systems R1801e ARM-based rack server
The R1801e server from ZT Systems doesn't just slap these ARM servers into a chassis, but rather connects them to each other with two Realtek five-port (4+1) Gigabit Ethernet switch controllers on the backplane. These switches have uplinks to the outside world so they can link to Ethernet switches in the racks and at the end of rows.
ZT Systems pre-installs Ubuntu Server as the default operating system on the ARM server nodes.
According to Travis Scott, a spokesperson for ZT Systems, the company is taking orders for the R1801e server today and can ship a box in eight to 12 weeks. Unlike the company's Xeon and Opteron rack servers, this machine is not a volume product yet, hence the long lead times. But, says Scott, ZT Systems wants to get on the front end of the ARM server boom and get a box into the field that lets hyperscale datacentres start assessing how ARM might fit into their workloads. The server is not cheap, however, at $20,000. But as volumes in the ARM server racket ramp up, prices will come down. This box is basically hand-made at the moment, and therefore expensive. That doesn't make it any less clever, of course.
The Cortex-A15 designs will pack up to 16 cores on a chip, and clock speeds are expected to go as high as 2.5 GHz, as El Reg previously reported. But these chips are not expected to start sampling until late next year. So the ARM-Xeon-Opteron war doesn't really get going in the server racket until 2012. This is just a skirmish to get the front lines skittish. ®