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Power7 - Big Blue eye on UNIX

Four server preemptive launch

The 770 and the 780

The Power 770 is a version of the Power 750 chassis that has two disk bays removed and the NUMA/SMP clustering bus added in. The Power 770 server node also has two GX++ slots per node, which means it can support a lot more 12X I/O drawers and therefore a lot more peripherals. Each Power 770 server node can have six disks or SSDs and has six PCI-Express slots. With the maximum of 16 12X-based I/O drawers, the machine can support 184 PCI-Express slots across four server nodes and 1,320 disk or SSD drives.

The Power 770 nodes have two flavors of processor cards: one using six-core Power7s running at 3.5 GHz (with 12, 24, 36, or 48 cores activated) and another using eight-core Power7s running at 3.1 GHz (with 16, 32, 48, and 64 cores activated). Main memory on the machine spans from 32 GB to 2 TB. To get memory capacity up to 1 TB means dropping the memory speed from 1.33 GHz down to 1 GHz, and going up to 2 TB means dropping down to 800 MHz. For some workloads, the lower speed of the memory will negate the extra capacity benefits.

The Power 780 is essentially the same machine as the Power 770 with three changes. First, it uses processor cards that have two sockets per card instead of one, which means it has double the processor cores. (However, the memory slots stay the same at 16 per processor card and the maximum main stays at the same 32 GB to 2 TB range per machine).

The second change is that it comes in the same enterprise-class, green-striped chassis that the Power 595 and System z mainframes have. (It has the skin of a mainframe, but the guts of a NUMA cluster with an architecture that IBM has been developing for a decade and selling for six years.) The other big change is the machine only has one set of processor cards, but they have two operational modes. In MaxCore mode, as IBM calls it, each node in the Power 780 cluster has four processor cards for between 16 and 64 cores running at 3.8 GHz, depending on if you buy one to four nodes.

If you happen to have a workload, like an OLTP system, that would do better having fewer cores running at a higher speed, you flip a switch in the microcode, reboot the system, and when it starts up you run in TurboCore mode. In this mode, the cores run at 4.1 GHz, but only half of them turn on. Those remaining cores in the system have access to both memory controllers on the Power7 chips and its full 32 MB of embedded DRAM L3 cache memory. For database workloads, TurboCore mode can boost performance by 20 per cent over MaxCore mode on the same physical machine.

IBM is not publishing pricing information on the machines yet, but Handy says that the memory price cuts that IBM made on Power6 and Power6+ systems back in November, where it cut DDR2 memory tags by between 28 and 70 per cent, were in fact setting the prices on older memory to the same level as IBM expected to charge for DDR3 memory on the Power7-based servers.

As for the systems themselves, IBM's plan is to hold prices roughly the same as the prior Power6 and Power6+ systems and give customers the extra performance. "This is very aggressive price/performance for us, and we are striking while the iron is hot," Handy says.

All of the Power7 machines announced today can support the current AIX 6.1 release as well as the earlier AIX 5.3 release. Customers using i/OS are going to have to move up to the i 6.1.1 interim release that was announced last quarter, and to fully exploit the Power7 feature set, they will have to wait to see i 7.1 later this year. (The word on the street is that i 7.1 will be available in the third week of April, but IBM did not confirm this).

Red Hat Enterprise Linux is not supported on these Power7 machines, which is a bit odd, but apparently IBM and Red Hat are working on it. Novell's SUSE Linux Enterprise Server 10 SP3 and 11 will run on the machines today. IBM plans to start shipping the Power 750 and 755 servers on February 19, The larger Power 770 and 780 machines will ship on March 16. ®

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