Sundry October Power Systems Announcements
October 16, 2017 Timothy Prickett Morgan
We had been hearing for quite some time that there might be some Power Systems announcements in October, and lo and behold there have been. They are just not what we had expected out of Big Blue.
The big news was not related to IBM i, which just had its Technology Refresh announcements two weeks ago for the 7.2 and 7.3 releases, but rather a big update for IBM’s AIX Unix variant as well as for the PowerVM hypervisor, the PowerSC security tools, and the PowerVC implementation of the OpenStack cloud controller, which does support IBM i systems. There was also some storage announcements that affect IBM i shops, as well as those running AIX and Linux, on Power8 iron.
Let’s start with the storage announcements because these directly apply to IBM i shops. In announcement letter 117-086, IBM has updated its 2.5-inch disk drives and flash drives for Power8 systems, and presumably these same units will be available in future Power9 servers. Disk drive technology is not getting faster, but the form factors are getting smaller with 1.8-inch and 2.5-inch drives being used in some systems as well as allowing more capacity to be crammed into larger 3.5-inch drives.
In this case of the 2.5-inch SAS drives that IBM is now offering on Power8 iron, the units spin at 15K RPM and come in 300 GB and 600 GB capacities and support 4 KB block sizes; they also have 256 MB of DRAM on the drives, which is used as a fast read and write cache that front ends the disk storage and boosts the overall performance of the disk. These new disk drives come in an SFF-2 carrier or tray format for Power8 servers or they can be mounted on an SFF-2 tray in the EXP24SX expansion drawer commonly used with these machines. Customers need a PCI-Express 3.0 SAS RAID controller to use these drives, whether in the system or the expansion chassis because older controllers don’t support the 4K format. The drives come in Linux-only variants as well as those that are formatted down for the IBM i platform, where they have 283 GB and 571 GB capacities. The 600 GB drive costs $550, or $1.83 per GB, while the 600 GB unit costs $1,025, or $1.71 per GB.
On the flash front, IBM has refreshed the mainstream 2.5-inch SAS flash drives in the Power8 systems with three new devices that weigh in at 931 GB, 1.86 TB, and 3.72 TB of capacity. These drives are formatted using 4 KB (mean 4,224 byte) sectors by default, and do not support 4,096 byte formats sometimes used in JBOF systems. The 512-byte (AIX and Linux) or 528-byte (IBM i) formats are not supported on this flash. IBM warns that these drives are not intended for heavy write environments. The 931 GB drive costs $2,275, or $2.44 per GB; the 1.86 TB drive costs $4,275, or $2.230 per GB; and the 3.72 TB drive costs $7,575, or $2.04 per GB. As you can see the gap between fat disk and way fatter flash, in terms of cost per unit of capacity, has come way down in the past several years.
AIX 7.2 Technology Level 2, which was unveiled in announcement letter 217-492, has some tweaks, and the neat one as far as I am concerned in a new feature that boosts the performance of AIX applications by exploiting shared memory connections using Remote Direct Memory Access (RDMA) protocols over InfiniBand and some Ethernet networks. This SMC-R support is an evolving standard that allows for TCP socket applications to transparently use RDMA, which cuts out the operating system kernel in handling memory-to-memory transfers between systems on a cluster. (RDMA underpins supercomputing, and InfiniBand took off because it had it first.) The CAPI peripheral bus support, which I am not even sure is available yet in IBM i for accelerators and flash storage, has been updated with performance enhancements in the AIX technology update (they are not called Technology Refreshes) while consolidating the flash disk and compute peripheral drivers into one device. It will be interesting to see how IBM deploys these technologies with IBM i systems, and I have been saying for a long time that these should be deployed. For instance, the RDMA and CAPI support woven together with some field programmable gate array (FPGA) compute engines, possibly on network cards, might to make a hardware assisted, high octane high availability clustering accelerator. You could implement much of the HA stack in FPGA code instead of running it on the CPUs, which are very expensive. Also interesting with the update of AIX is the AIX Toolbox, which includes Ansible, Python, and several open source packages. Whatever is not already supported in IBM i natively in this toolkit should be brought over using the PASE AIX runtime.
The PowerVM V2.2.6 enhancements, outlined in announcement letter 217-494, include tweaks to interface between the hypervisor and logical partitions running IBM i, AIX, or Linux and flash to automagically cache data to the flash for the partitions to accelerate them. This caching allows for active/active concurrent access across partitions and is compatible with Live Partition Mobility live migration of partitions. Here is the interesting bit: IBM warns in this announcement letter that the Power8 chip will be the last processor to support the Integrated Virtualization Manager for spinning up partitions quick and easy without the full-on PowerVM, and adds that VIOS 2.2 will also be the last virtual I/O driver that supports IVM. Hmmmm.
Another cool bit of software is called Cloud PowerVC Manager for Software Defined Infrastructure, unveiled in announcement letter 217-507, and that is a funky way of saying it is an OpenStack cloud controller mashed up with a variant of IBM’s General Parallel File System (GPFS) for supercomputers, now called Spectrum Scale, that has been morphed to look like a parallel and virtual SAN for cloudy infrastructure setups. It looks like it might even be hyperconverged, meaning it runs compute and storage on the same nodes in a cluster of machines. It costs $1,600 per socket, which is not a bad price for IBM software. I am going to have a think about how this might be useful for IBM i shops or not.