HA4i running in production and performance is better than expected

HA4i Version 7.1 was announced a few weeks ago now and we have been upgrading the current HA4i V6R1 customers to the latest version. After a few initial teething problems we are seeing a big improvement in the performance of the new apply process over the existing APYJRNCHG process. The main reason for this is the lack of locking and unlocking of files every time the receiver changes, with the APYJRNCHG command we would see all of the files locked before any journal entries would be applied. In most customers this is not a problem, but in those where there are thousands of files defined to a single journal it could cause some delays while all the files are locked prior to the updates being applied. This was in fact one of the major reasons we decided to create our own apply process so we could control just what was locked and when especially as IBM was unwilling to change any of their processes which we relied on.

The new apply process now locks a file only when it has updates to apply, this has provided us with tremendous catchup capabilities because it is only opening files as updates are seen. In one case the client had over 30,000 files defined to a single journal, with the new apply the most files we have ever seen open is just over 200, this means the journal has over 29,800 files which are never updated yet would have required locking each and every time the IBM apply process was run.

The new apply process is providing many more benefits than we first expected and we are continuing to improve its performance and capabilities. if you are looking at High Availability HA4i should be on your list of solutions to consider.


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About Chris Hird

Chris Hird President and Owner Shield Advanced Solutions. Hird first worked with high availability at IBM Havant in the United Kingdom in 1989, and he was responsible for the technical interface with the developers of HA products and setting up a support structure in the UK to support the IBM customers. He left IBM to set up Shield Software Services in 1993, which was an IBM business partner and a MiMiX reseller, and in 1997 he moved to Canada and launched Shield Advanced Solutions, which provides tools and utilities aimed mainly at supporting HA Environments. Programs in C and PHP on the i5.

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