Vision Cuts Downtime Associated with HA Replication

Published: June 20, 2006

by Alex Woodie

A problem with high availability replication on the iSeries has been the need to periodically restart the servers to reset the journal sequence numbers. This problem is mostly relegated to very large iSeries shops, which, unfortunately, is exactly the type of customer with the most to lose from downtime. Vision Solutions will soon be shipping a new release of its Orion high availability software that eliminates this downtime requirement through support for IBM's *MAXOPT3 feature in OS/400, among other enhancements.

Vision Solutions last week announced that ORION for i5/OS version 1.2 Service Release 2 is in limited availability, with general availability expected by mid July. This SR-2 release features a range of enhancements to the Datacenter Edition version of ORION, which is the core product the company developed and sold before its acquisition of OS Solutions last year. The company is also working on a new release of ORION for i5/OS Standard Edition, which is the remote journaling-based HA product from OS Solutions. Despite the similar names, these are separate products, although they do share some of the same tools.

With last week's announcement, Vision is concentrating on improving the manageability of ORION Datacenter Edition, and reducing the amount of care and feeding that running an OS/400 high availability environment requires. It has also made some performance enhancements to the replication process.

Supporting the *MAXOPT3 option that IBM first added to OS/400 V5R3 will have the biggest impact on high volume replication environments. The feature increases the maximum number of journal sequence numbers--required for each replication transaction--from 9,999,999,999 to 18,446,744,073,551,600, according to Vision.

Doug Piper, Vision's director of product strategy, says *MAXOPT3 support is an important feature for Vision's larger customers. "With the smaller sequence size, customers with larger databases and more transactions were finding they had to do journal sequence resets, which requires them to bring their system down to reset their journal sequence number," he says.

Some of these customers were taking their servers down once a month to reset their journal sequence number, Piper says. The new feature should reduce this costly maintenance requirement. "With the larger *MAXOPT3 journal sequence size, customers can almost indefinitely run their systems without reaching the maximum number of journal entries." And when a journal sequence reset is required, the SR-2 release of ORION will handle it automatically, without requiring downtime.

ORION Datacenter Edition also gains new features for mirroring logical files. While Vision has always been able to mirror logical files with its product, changes were required to support the new types of journal entries that IBM introduced with OS/400 i5/OS V5R4. Instead of replicating the entire object, as was required with previous releases, ORION Datacenter Edition can replicate just the individual logical files supporting the new journal entry types.

Support for mirroring logical files will make ORION Datacenter Edition run more efficiently, says Carl Hillier, a senior product manager with Vision. "Previously what we would have to do is copy the file, even though you just changed the name," he says. "Our software now effectively says, 'Just rename the file.' That's a hell of a lot more efficient."

Performance is further boosted with enhancements in the area of journaling minimized data. While using minimized data can boost replication speeds, the use of minimized data introduces certain complexities into the equation, Piper says. To address these complexities, Vision developed a form of its Cyclic Redundancy Check (CRC) that is used to validate the integrity of minimized data going into the journal.

The SR-2 release also brings support for mirroring of OS/400 spool files in independent auxiliary storage pools (iASPs) in ODS/400, the object mirroring engine in ORION Datacenter Edition. "We previously supported iASPs, we but didn't include support of spool files," Piper says. Lastly, this release brings improved support for clustering-based role-swaps, enhancements for its group mode support, and support for i5/OS V5R4.

Vision also shared with the IT Jungle details of its ORION product roadmap. The Irvine, California, company is working to build performance-acceleration technology into the product that will enable "intelligent" processing of transactions.

"If you look at the different types of high availability replication out there--journal-based mirroring and file-based--this will give you the capability to look at the transactions and optimize how you deal with them," Piper says. It will involve "intelligent replication and doing optimization using some sophisticated internal technology for caching and hashing to give us some improved overall performance. That will be detailed in our GA announcement."

Piper says the new technology could boost the speed of some replication environments by 400 percent, and enable peak loads of 200 to 230 million transactions per hour, although he says tests show the benefits will vary considerably depending on the customer's specific environment. "It's yielded some really impressive results for some of our customers," he says.

In the meantime, Vision customers will benefit from the performance improvements in ORION for i5/OS Datacenter Edition version 1.2 SR-2. When it ships, it will be available in four varieties, including Express, which ranges in price from $5,000 to $30,000; Professional, which ranges from $6,000 to $50,000; Enterprise, which ranges from $25,000 to $400,000 or more; and Advanced Enterprise, which ranges from $50,000 to $500,000 or more. For more information, visit www.visionsolutions.com.