Sundry April Power Systems Announcements
April 18, 2016 Timothy Prickett Morgan
As we reported last week in discussing IBM‘s Power processor roadmap for the next five-plus years, there is not going to be a Power8+ revamp of existing Power Systems machines. Instead, IBM has rejiggered the Power8 chip to create a variant aimed at supercomputing and deep learning workloads that allows for high-speed NVLink coupling between Nvidia “Pascal” Tesla GPU coprocessors and the Power8 chip.
That means there is no performance boost or list price cut (or both) that is normally expected and delivered with a “plus” variant of the Power chips. But as we expected, IBM has made a few tweaks to the Power Systems portfolio outside of the release of IBM i 7.3 and a Technology Refresh update for IBM i 7.2.
First up, IBM has goosed the memory capacity on the midrange Power E850 server, mirroring the memory boost it provided on the high-end Power E870 and Power E880 machines back in February. The Power8 machines, you will recall, are based on DDR3 memory chips and make use of Big Blue’s “Centaur” memory buffer chip, which allows IBM to scale up memory bandwidth on its systems and have a lot of memory sticks hanging off of a single processor socket, boosting the memory-to-processing ratio of the system. IBM makes its own CDIMM memory cards for its Power Systems line (or rather, designs them and contracts them out), and the fattest ones come in a 256 GB capacity, twice that of the top-end 128 GB CDIMM modules that IBM shipped initially with the enterprise-class Power Systems bearing the E870 and E880 label and scaling to four, eight, or 16 sockets in a single NUMA system image.
In announcement letter 116-029, IBM launched support for the fatter 128 GB CDIMM memory cards in the Power E850 servers, doubling their top-end memory capacity to 4 TB. Previously, it had only shipped CDIMMs with 64 GB capacities, which topped the memory in the Power E850 at 2 TB across four sockets. We are reasonably certain that if a customer wanted to double up the memory capacity again on a special bid basis, IBM could put the fattest 256 GB CDIMMs in the Power E850 (perhaps as a fat node in an in-memory database cluster) The feature #EM8S 128 GB CDIMM memory card costs $6,145, according to the price list, but this looks wrong to me. It is way too low. IBM charges around $156 per GB for the 256 GB card, which is the same price IBM was charging for the 128 GB cards on the bigger Power Systems machines. The price list also says that this is a DDR4 memory module, which I do not believe it is since IBM was not expected to move to DDR4 main memory until the Power9 chip next year.
In addition, IBM has announced a four-port PCI-Express RAID SAS adapter with 12 GB of cache memory that is aimed at boosting the performance of flash SSDs on Power Systems iron. A pair of controllers using RAID 0 mirroring on SSDs was able to chew through 1.6 million I/O operations per second (IOPS) reading random data in 4 KB blocks; with RAID 5 data protection, the pair of controllers could hit 360,000 IOPS writing data randomly in 4 KB blocks; and with a mix of 70 percent reads and 30 percent writes (a common distribution in the storage industry) was able to process data at a rate of 878,000 IOPS. The 12 GB adapter (feature #EJ14, and designated as a “plus” variant of an existing feature #EJ0L card) costs $7,000, and it is only available on machines using the Power8 processor.
If you want to bypass the PCI-Express software stack and get even lower latency with flash drives, IBM has introduced two flash drives in an SSD form factor that support the NVM-Express protocol. Features #EC54 and #EC54 have 1.6 TB of capacity and feature #EC57 has a 3.2 TB capacity. These NVM-Express drives offer up to 750,000 IOPS on random reads and 3 GB/sec of sustained bandwidth with latency on writes as low as 25 microseconds. They are supported on Power S812L, S822L, S824L, S814, S822, S824, E870, or E880 machines and will soon be supported on the Power E850 machine. Ah, but here is the catch: The machine has to be running Linux to use these fast flash drives. No word on when AIX and IBM i will get support, but they certainly should. The 1.6 TB unit costs $7,999 and the 3.2 TB unit costs $14,999.
If you want regular, plain vanilla SSDs that do not have the benefits of the NVM-Express protocol (which cuts out a lot of the SCSI chatter in the PCI-Express protocol that has no bearing whatsoever on flash memory), then IBM does have its fourth generation of flash SSDs that do plug into Power8 machines and that do support IBM i 7.1, 7.2, and 7.3. These new SSD are outlined in announcement letter 116-036. These new enterprise MLC flash drives come in a 2.5-inch form factor and come in 387 GB and 775 GB capacities as well as a new 1.55 TB capacity. These drives have about 50 percent better higher IOPS on mixed read/write workloads and an average latency of around 12 microseconds, which is 20 percent better than the third generation of SSDs sold by IBM in the Power Systems line. There are a slew of feature numbers for these drives, depending on if you want to install them in Linux-only or multi-OS Power Systems machines, and the 1.55 TB SSD is only available on Power8-based machines. The 387 GB drive costs $2,649, or $6.85 per GB, while the 775 GB drive costs $4,449, or $5.74 per GB, and the 1.55 TB drive costs $7,779, or $5.02 per GB.
In addition to these general purpose 2.5-inch drives, IBM has a 1.8-inch SSD in a 387 GB capacity also based on eMLC4 flash technology that costs $2,399, or $6.20 per GB, and a 775 GB version, which costs $4,199, or $5.42 per GB.
Finally, there is a new 2.5-inch SAS SSD that is specifically designed for read-intensive workloads and that comes in a 1.9 TB capacity. This drive costs $4,399, or $2.32 per GB.
This would have been a lot more fun, obviously, if there were actual Power8+ servers. It will be a long, long way until Power9 machinery will be announced sometime in the second half of 2017. Until then, IBM should do some wheeling and dealing on its existing Power8 systems, particularly with Intel applying the competitive pressure with its latest “Broadwell” Xeon E5 v4 processors, launched two weeks ago.