iSCSI for System i Update: Showing Some Promise
November 27, 2006 Dan Burger
The idea of bringing external System x and xSeries servers under the skins of System i servers seems to be picking up speed. It’s difficult to gauge how much speed, because IBM plays the “if I told you, I’d have to kill you” game when it comes to specific adoption rates, but it’s a good bet that the new iSCSI adapters and the increasing popularity of BladeCenter blade servers are responsible for a momentum in this area.
For those who are relatively new to the Windows integration game, the iSCSI (Internet SCSI) connection, which links external servers to the disk arrays inside the System i5 servers, became available in May. It will eventually replace the Integrated xSeries Server card, a Pentium co-processor card, and the Integrated xSeries Adapter, an adapter card for a funky Fibre Channel variant that IBM calls High Speed Loop. The IxS has been around for more than a decade, and the IxA made its debut a few OS/400 server generations ago as customers needed more oomph than customers could pack on a single processor card. The reasons to integrate these systems most often come down to storage–using the System i essentially as a storage area network (SAN)–for Windows and now Linux workloads. (It used to be NetWare and OS/2 as well, many years ago.) The IxS and IxA approach also allows for easier management of the X86 and X64 systems, since OS/400 and i5/OS can wrap around other platforms and make them more reliable and secure. This improves resiliency and lowers the cost of managing Windows and Linux servers.
Last week, I spoke with Kyle Wurgler, the product manager for System i integration with BladeCenter and System x servers at IBM. He’s on the front lines of promoting the iSCSI product and has a vested interest in its success. Naturally, his viewpoint is pretty much one-sided, but his insights are nonetheless valuable. iSCSI technology is still in its infancy when it comes to the System i market. It requires the latest version of the operating system, V5R4, so that alone limits the number of shops that can make use of it. Wurgler’s job is as much about education and getting the word out about iSCSI as it is about installation and implementation. And to that end, he will be presenting this topic in a Webcast December 6. It’s only available to members of the COMMON user group, but if you or your company has a COMMON membership, you can register for Wurgler’s presentation, which begins at noon CST.
Wurgler dances around the question of how many System i customers have purchased and implemented iSCSI hardware during its first six months of availability. His first comment on this topic is “I have had hundreds of customers order this product–more than 200, but we are not to the thousand mark yet.” After a bit of a pause for further consideration, he comes back with “closer to the 500 mark . . . I’m guessing . . . somewhere in the 500 to 800 range.” As you can see, this game of getting good data from IBM is a little bit like playing darts with your eyes closed, but you get an idea of where the adoption rate is. Again, you have to keep in mind that the number of systems running V5R4 is not likely to be more than 10,000 at this point in time.
The availability of iSCSI has not put the IxS and the IxA on the shelf, but it will. Currently, the products co-exist and the official word from IBM is that IxS and IxA will be marketed at least until the mid-2008 timeframe and supported beyond that. Wurgler says there are no product upgrades expected for IxS. The IxA adapters will support fewer System x boxes as newer units become available and the ports are eliminated.
The IxS and IxA products have inherent limitations that have kept the lid on implementations the number of xSeries servers that could be attached was only 18 for IxS and only 8 for IxA when configured on the most popular System i, the i5 520. If you go back to the iSeries 800, only four IxS servers could be plugged into the boxes, and only three could be integrated via an IxA card. On an iSeries 810, it was only 13 IxS co-processors and seven IxA cards, respectively.
“With the IxS and the IxA, customers were from a group that was going to integrate less than 30 Intel servers,” Wurgler says. “With iSCSI, it takes the top-end cap off. We have talked with customers that are looking at integrating 70 or 80 servers. The combination of iSCSI and BladeCenter is definitely opening new doors and bringing new integration customers.”
How many iSCSI customers are new integration customers and how many are former IxS and IxA customers is not clear. That’s another topic where specifics are not being shared. Wurgler says “it’s a mixture of both.”
What is clear is that the market for consolidating Windows and Linux boxes on System i boxes relies almost entirely on System i customers. Companies that don’t have a System i are not likely to buy one for consolidating storage and ease of administration purposes. Trying to find a deal where a new iSeries or System i server was sold because the company wanted it for the purpose of consolidating X86 or X64 servers takes a lot of digging. The point of bringing that up is only to note that although this is a solid benefit for System i shops, it will not be a factor in building out the platform’s ecosystem, and that continues to be a worry.
How important this Windows and Linux integration opportunity becomes remains to be seen. It’s fair to say that the IxS and the IxA have not had much impact. However, Wurgler says it’s a misconception that shops have used the IxS and the IxA approaches primarily for running file and print servers. “I have customers running Citrix servers, SQL Servers, JD Edwards, Exchange, WebSphere, Domino, resort management and reservation systems, and almost every application under the sun,” he says. “Customers are looking at bringing on more servers because of the cost savings and because blades are a catalyst to bringing on more servers. When people buy a BladeCenter chassis, they plan on adding at least six servers, because the price point would be cheaper to buy individual servers if six or less are required. A blade server is actually increasing the number of servers that people are going to need. Once you buy a blade, adding more blades is pretty easy.”
As Wurgler sees it, getting a handle on all the blades is one of the major system administration benefits of the iSCSI link to the System i server. Neither the IxS nor the IxA has BladeCenter integration capabilities. One thing they do have is a reputation for sluggish performance when running applications that could use more horsepower than a single 2 GHz processor can deliver and more than 2 GB of memory, albeit that is plenty of power for a lot of X86 and X64 workloads.
When talking about iSCSI on System i, the discussion needs to include the skill sets required to install and implement it. iSCSI takes SCSI commands and encapsulates them into TCP/IP packets. So, to begin with, a customer needs to have some networking skills. Wurgler makes presentations at conferences, user group meetings, and at customer sites. He’s seen both sides of the skill set spectrum. “Some buy and implement it on their own or with the help of a partner. Others hire all the implementation services,” he says. “It’s not impossible for the majority of our customers to implement this. But I can 100 percent guarantee, it would be difficult for them to do it without reading the documentation.”
If you want to determine where your staff is in terms of the required skills, Wurgler recommends reading iSCSI Install Read Me First. “It is the bible for installing this technology. The success ratio for implementation is much higher for those who read it.”
IBM Delivers iSCSI Connection, Pushes Blades to OS/400 Shops