Thousands of HP e3000 sites are preparing for an upgrade over the next few months, and HP is now advising them their performance can vary when moving to the latest operating system. A note released to the HP 3000 division’s (CSY) channel partners reports that some HP 3000s actually run slower under 6.5 — and that slowdown has nothing to do with the performance bug HP introduced in PowerPatch 1 for 6.5 (there's a fix for that bug in general release). The decrease varies, according to HP’s Kevin Cooper, the engineer who leads CSY’s re-architecting of performance for new e3000 platforms and new releases.

Cooper authored the note which reports that “Some users have noticed a slight change in system performance after going to the 6.5 release, when doing heavy file system IO to MPE fixed-record flat files. New functionality allows these files to be larger than 4Gb in size, which required the code which accesses them to increase in size. Reads or writes to these files may take somewhat longer to execute on 6.5. HP believes that on most systems, this should not be noticeable, because the amount of CPU time the system spends processing disk IOs is small, compared to the other processing on the system. But users may notice that some batch jobs which do heavy disk IO to MPE fixed-record flat files may run slightly longer.”

Not all of the division’s messages about the 6.5 release have contained this warning. Cooper’s talk on the release at HP World did, while pointing out 6.5 boosts Series 997 customers running more than eight processors. But customers say when calling for advice on an upgrade — because the 5.5 release goes off HP support on December 31 — they get told by HP to move to 6.5 if at all possible. That’s because HP put its best foot forward to help generate adoption of the 6.5 release, with articles promoting 6.5 as the next step for e3000 operating systems. Cooper’s note says that 6.5 “is a ‘high-end’ performance release, which can provide significant performance benefits to customers with large multi-processor systems based on HP’s 64-bit PA-8000 and PA-8200 processors. Smaller systems, and those with earlier processors, should not see much of a performance difference when updating to the 6.5 release. Most systems should run at about the same performance level on 6.5 as they did on releases 5.5 and 6.0. But the 6.5 release will use slightly more memory on a system.” Cooper said 128Mb is the minimum for production systems running 6.5.

Testing of 6.5’s performance impact inside the CSY labs included production runs of the Amisys healthcare application and the Smith-Gardner MACS/Ecometry application, plus other apps. The Amisys and S-G apps showed no decrease, Cooper said, but in a worst case with other tests, “we saw a 10 percent degradation.” On average, the release ran those other applications a few percent slower in overall system throughput, “which is not looking at any one process somebody does on the system. It looks at a mix of online and batch usage in the typical system environment.” The performance hit doesn’t appear during database access — 6.5 was database “performance-neutral,” Cooper said — but it shows up during FREADs and FWRITEs to MPE flat files.

Some users don’t have a choice in upgrading from 5.5. Suppliers of applications tested in CSY labs are mandating a path to 6.5; Amisys customers were to be on 6.5 by this month, running the release that HP tuned to make the application faster. Smith-Gardner issued a memo to customers saying that June, 2001 would be the end of its ability to ship fixes to its 6.0-using customers: “Once we upgrade our development systems to MPE/iX 6.5, we will no longer be able to send code to a client who is on a previous version of the operating system,” the S-G memo stated. But sites running home-grown apps have an option of upgrading to the 6.0 PowerPatch 2 release, which doesn’t have the performance issues of 6.5 because it’s not ready for files larger than 4Gb.

HP has said 6.0 will be supported until April, 2002. If you don’t go to 6.5, you miss the chance to have a Secure Web Server on your 3000, support for more than 3.75Gb of RAM (if your 3000 uses either PA-8000 or 8200 processors) as well as that large file support. The 6.5 performance degradation in some cases is pretty hard to see — a slowdown Cooper said was at “the point where very few customers are going to notice that — only the people that are already running at 100 percent now.” Operating system upgrades usually demand more performance, the cost of more features. To decide what’s acceptable, test before committing to 6.5.