Memory and more memory
The HX5 blade has room for two 50 GB solid state disks (one comes standard), and 16 DDR3 memory slots and IBM is supporting very low profile memory due to the skinniness of the blades, but is only selling standard voltage memory. (Maybe the Xeon 7500s do not have support for low-voltage memory like the Xeon 5600s just got? That probably comes with the Xeon 7600s).
IBM is supporting 4 GB and 8 GB memory sticks in the machine, which means memory tops out at 128 GB per two-socket blade. In its preview, IBM said that it had a memory blade add-on called Max5 that would allow an extra 24 memory slots for a two-socket blade as well, which adds another 192 GB of memory potentially.
IBM said back then than only one Max5 memory extender would be permitted on either a two-socket or four-socket blade, but this turns out to be not true. You can put one Max5 on each two-socket blade and then plug all four blades together into a big SMP server with four sockets and 80 memory slots, for a maximum of 640 GB of memory. All in about 2.5U of equivalent rack space.
Some HPC shops are going to love this. Four of these blades could be the new fat node in a cluster. Unless they get a look at the System x3850 X5 and x3950 X5 4U rack-mounted machines, or the System x3690 X5, a 2U rack server that was not announced yet but IBM said was in the works back in March.
The System x3850 X5 machine is the basic four-socket server node that has been at the heart of IBM's high-end x64 range for many years. IBM's homegrown eX chipsets allowed for one, two, four, and sometimes eight of these nodes to be linked together into a NUMA system. The x3850 X5 will eventually scale from one to four chassis, which is a 16-socket box potentially using top-end eight-core parts, for a maximum of 128 cores.
For now, it looks like IBM is only selling single-node x3850 X5 machines, with the two-node scalability kit coming on June 15 that turns it into a System x3950 X5. The Max5 memory extender for this box, which IBM was talking about back at CeBIT, is not yet available either. And there's no word on when the three- and four-node scalability kits for larger x3950 X5 machines will arrive.
The x3850 X5 has four processor sockets and IBM is supporting all eight variants of the Xeon 7500s in the machine, from the six-core, low-voltage 1.86 GHz L7545 all the way up to the eight-core, 130 watt 2.26 GHz X7560. IBM warns that the E7520 and E7530 parts, which are four- and six-core parts, cannot be used in eight-socket and larger configurations. IBM is supporting 1 GB and 2 GB DDR3 memory sticks running at 1.33 GHz and 4 GB and 8 GB sticks running at 1.07 GHz. IBM is also one of the first vendors out the door with 16 GB memory sticks, which the x3850 X5 supports as well.
This memory is plunked onto system memory cards with Intel's Scalable Memory Buffers, which bear some resemblance to the buggered memory cards IBM has used in Power Systems for years. With 16 GB DIMMs, which no one can afford right now, IBM can cram 1 TB of memory into a 4U chassis or 2 TB in an eight-socket box in two 4U chassis. The Max5 memory extender will add another 32 memory slots to the box, meaning customers can use less capacious and less expensive 4 GB and 8 GB memory sticks to put a still hefty 384 GB or 768 GB of main memory on a four-socket or eight-socket box, respectively. (That's provided IBM allows one Max5 memory expansion unit for each node).
The x3850 X5 has five PCI-Express 2.0 slots (one x16, five x8, and one x4), and redundant 1,975 watt power supplies. It has eight hot-swap, 2.5-inch SAS disk bays that support disks of up to 500 GB of capacity. If you want to go SSD, then you can jam 16 of the 50 GB SSDs into the bays.
IBM has certified Microsoft's Windows Server 2008, Red Hat's Enterprise Linux 5, Novell's SUSE Linux Enterprise 11 operating systems on the Nehalem-EX iron, with VMware's ESX Server 4.0 and ESXi 4.0 hypervisors also being certified on the machines.
In a base configuration with a single four-core 1.86 GHz E7520 processor and 8 GB of memory, the BladeCenter HX5 blade costs $4,629. With two of the six-core 2 GHz E7540 processors and 64 GB of memory, the HX5 costs $15,095. In a base configuration with two of the quad-core 1.86 GHz E7520 processors and 4 GB of main memory, the x3850 X5 costs $9,049 (there's no disks in that configuration). A machine with two of the eight-core 2.26 GHz X7560 chips and 16 GB of memory jacks the price up to $21,705.
In many ways, the two-socket x3690 X5 machine, which has not been formally announced yet, is more interesting. Like the HX5 and the x3850 X5, the x3690 X5 offers the FlexNode upgrade capability, so the 2U box can have another one slapped next to it and use IBM's eX5 chipset to convert it to a four-way server.
The x3690 will have 32 of its own memory slots, and another 32 can be added using the Max5 memory expansion module, for a stunning 1 TB of memory (using 16 GB DIMMs) for a two-socket box that tops out at 16 cores. Even with 8 GB memory sticks, the x3690 X5 can wield 512 GB of memory, which again makes it a perfect fat node for certain supercomputing workloads. The x3690 X5 may come in a 2U form factor, but it has enough room for 16 2.5-inch, front-mounted disks. ®