The face of disk storage on the iSeries is moving external. Market experts predict that the future will be filled with multiple operating systems and growing data sets, requiring external disk to accommodate these expanding storage needs.

      “My bold prediction is that internal disk is going to phase out completely for the iSeries, and that there will be a big push to SAN. If shops are going to use the iSeries as a universal box and are making the move to run multiple operating systems and LPARs, then they need a different disk solution to accommodate all of that. If they stay with internal disk but want to do all of these things, they will not have the flexibility to move things around and switch between operating systems,” says David Breisacher, CEO chairman, GST Inc., Irvine, CA.

      The decision to go with internal disk instead of external disk on the iSeries has been a no-brainer for shops in years past — internal disk goes hand in hand with the integrated iSeries platform. But now, with the ability to run multiple operating systems in multiple partitions, iSeries shops are considering external disk as a more suitable approach.

      “The new features and functions of the operating system in V5R3 allow the iSeries to connect more eloquently to an external disk/SAN,” says Pete Elliot, director of marketing, Key Information Systems, Los Angeles, CA.

      Market experts agree that external disk is at the forefront of storage on the iSeries, but they don’t all agree on the reasons why. According to Elliot, the push to external disk on the iSeries stems from businesses’ growing demands for making data readily available.

      “I don’t think that multiple operating environments and multiple LPARs will be the driving force behind going with external disk on the iSeries. It really comes down to the business environment. If a company uses and exchanges large files, and serves that data out, the key will be to do that externally. Our demands on data are pushing it to be more dimensional, and that is pushing storage through the roof,” says Elliot.

External disk for the growing business

      Whether the push to go external comes from running multiple operating systems or from using large data files, external disk offers enterprise-level companies with a much-needed alternative.

      “The recent push to Shark and SAN is the result of increased customer demand. Today, more mid-sized businesses need to manage large environments in their data centers, and external disk offers a solution to manage that on a central frame. The need for external disk is already out there because so many mid-sized businesses have enterprise-level needs but don’t realize that a SAN can be the solution to their storage problem,” says Rick Aguiar, iSeries chief technologist, EMC, Hopkinton, MA.

      According to Breisacher, the largest benefit of implementing an external disk solution is overall flexibility. “If shops are running multiple operating systems and LPARs, they will want external disk because it gives them more efficiency, the flexibility to switch between platforms, and more possibility for growth. Internal disk in the iSeries is restrictive because all of the disk space is allocated to the iSeries,” says Breisacher.

Customers still reap benefits from internal disk

      The flip side of the external disk dispute lies with IBM’s future direction for storage on the iSeries. “I don’t see IBM letting go of internal storage on the iSeries — that is how it maintains the reliability of the platform. If shops are looking to consolidate their servers, why would they go with external disk when the iSeries already has storage built-in. The iSeries is almost its own SAN environment already,” says John Gimpl, executive vice president, eStorage Inc., Irvine, CA.

      Gimpl contests that internal disk is the most appropriate storage solution for shops that utilize the iSeries for the majority of their applications and workload, and external disk is appropriate for shops where the iSeries only accounts for approximately 20% of the workload.

      “We [eStorage] will continue to focus on internal disk on the iSeries as long as IBM continues to develop and utilize internal disk on the iSeries. I can tell you that we will be releasing a wider line of products in the future. As soon as a faster, more reliable, more manageable, and more cost-effective solution becomes available, we will launch our own version. But today, performance and reliability lie with internal disk on the iSeries,” says Gimpl.