All Kinds of Goodies Added to IBM i 7.1
April 25, 2011 Timothy Prickett Morgan
It’s no secret that I like hardware, but I am the first to admit that the endless progression of hardware improvements is merely there to make software run better, faster, or more reliably. The hardware is the easy part; the software is the hard part and it therefore moves a lot more slowly on the evolutionary scale than hardware. That said, companies like to roll out new software releases with new hardware releases to give customers twice as many reasons to think about spending some money.
And so it was with the Power Systems announcements on April 12. As The Four Hundred reported in last week’s issue, IBM has doubled up the processor sockets on its Power7-based blade servers using slower 2.4 GHz chips while at the same time goosing the clocks speeds a bit on the processors used in the workhorse Power 750 four-socket box. IBM has also introduced new I/O options, as we report on elsewhere in this issue and cut prices on various disk and memory features. Think of it as spring cleaning in Rochester, Minnesota.
As you might expect, many of the enhancements that Big Blue is putting out for IBM i 7.1, which you can read all about in announcement 211-108 and which start shipping on May 13, have to do with enabling the operating system to support the new hardware, which will be available a week later on May 20. This includes the new processor, disk drives, solid state drive, networking adapters, and I/O expansion drawers that were announced on April 12. (But don’t get the wrong idea. The new two-socket PS703 and four-socket PS704 blade servers also support the earlier IBM i 6.1.1 release.) Ditto for the new Systems Director Management Console, the replacement for the Hardware Management Console that I told you about here.
But a bunch of the enhancements that IBM has cooked up for IBM i 7.1 have nothing to do with new hardware but are rather just ways to make the system work better. Some of them are simple. For instance, if you want to run i5/OS V5R4 or IBM i 6.1, 6.1.1, or 7.1 on a Power-based blade server, you know that you have to configure at least one blade in the chassis with the Virtual I/O Server (VIOS), a partition on the PowerVM hypervisor that acts to virtualize disk, tape, and networking I/O for the i5/OS and i operating systems. (I don’t know this, but I suspect IBM propped the OS/400 progeny on VIOS so it didn’t have to pay to write native drivers.) AIX and Linux customers have the option of using VIOS to virtualize peripherals, but they also have native drivers for peripherals. The problem with VIOS, and one that makes IBM i shops a little jumpy perhaps, is that a single VIOS partition represents a single point of failure for a whole bunch of PowerVM logical partitions supporting IBM i workloads.
And so, starting with the May 13 update of IBM i 7.1, BladeCenter machines running IBM i and using VIOS to virtualize I/O can now have mirrored, redundant VIOS instances, eliminating a single point of failure from the blades. The Power6 and Power7 rack and tower servers have already been giving their redundant VIOS support, by the way, which also includes multipathing through the two VIOS instances to link a server blade to various storage devices. You’ll have to move to the new SDMC console, however, to take advantage of it.
The PowerVM hypervisor running IBM i 7.1 now has a suspend/resume button, like that on your stereo or multimedia player of choice, so you can stop the partitions if you need to free up resources for other jobs and then resume them at some future point. The suspend operation, says IBM, saves the state of the partition, including cache memory, main memory, and service processor state, onto persistent storage (flash or disk). When you hit resume, a partition is given all that state back again and picks up running the applications from the exact point where it was frozen. To make use of the feature, you need to be at i 7.1, you have to use VIOS to link to all I/O resources on the partition, storage must be external to the system, you have to use an HMC or SDMC to manage the partition, and you have to resume the functioning of the partition on the same server it was suspended upon.
Here’s another new one for IBM i 7.1 that was originally available with i 6.1 and 6.1.1 that is now coming to the more recent release. Although IBM didn’t say it this way at the time, those older releases had a way of taking a logical partition running IBM i and designating it as what is, for all intents and purposes, a kind of limited VIOS that is based on the OS/400 codebase instead of the AIX codebase. To do this, you designate an IBM i partition that has optical drives or DAT or LTO tape drives as the “server partition” and then other “client partitions” on the same physical Power Systems machine and also running IBM i can access those peripherals through that primary partition over a virtual SCSI link. (You can read all about it here.) The point is, with the May 13 update of IBM i 7.1, now you can do this on i 7.1 partitions acting as the “server partition, providing access to LTO3, LTO4, LTO5, DAT 160, and DAT 320 tape drives and TS2900, TS3100, and TS3200 tape libraries to i 6.1.1 or i 7.1 partitions on the same machine.
IBM has also announced that i 7.1 partitions running on Power6, Power6+, or Power7 servers support N_Port ID Virtualization (NPIV) attachment of DS5100 and DS5300 external disk arrays to those partitions. As I explained back when i 6.1.1 was released in October 2009, the initial NPIV support allowed i 6.1.1 to link out through native Fibre Channel adapters in a Power Systems rack or tower server (but not a blade server, which required VIOS to link to peripherals) and talk directly to storage area networks. That NPIV support allowed high-end DS8000 disk arrays and midrange TS3100, TS3200, and TS3500 tape libraries to be hung off i 6.1.1 partitions while letting the full feature sets of the arrays be accessible to the operating system.
IBM says it has also tweaked the multipath I/O capabilities with i 7.1 so you can set up multiple paths between a server and its external or VIOS-attached storage arrays that don’t have exactly the same physical hardware and therefore the same basic performance characteristics. This means you can run a little cheaper on the redundancy, but the algorithms are now smart enough to take the higher-performing path if it is not being saturated by I/O requests. This improved multipathing I/O support is also, says IBM, particularly useful when an adapter is being shared by multiple logical partitions that have very different workload characteristics. In those situations, you can’t just divide the card into equal slices and expect different-sized partitions to behave well as they hammer with virtualized adapter.
IBM also put some tweaks into the DB2 for i relational database management system that is integrated with the i 7.1 operating system. IBM has been tweaking how the operating system makes use of the I/O-dripping capabilities of solid state drives (SSDs), and now it has “more granular database object placement,” down to the file member level, in fact. The database objects can be moved from disk to flash while the database is in production now, too, but it is not clear if this is done automatically by the system (as it should be) or if database/system administrators have to do it manually (which defeats the whole AS/400 value proposition if this turns out to be the case). There are a number of SQL and XML performance enhancements, and the SQL Query Engine in i 6.1 has been backcast with optimizations that were originally only available with i 7.1.