An enhancement has been made available in IBM i 7.1 and 6.1 releases that may help with integrated file system SAV performance. A new parameter, Asynchronous Bring (ASYNCBRING) has been added.
The ASYNCBRING support enables objects to be asynchronously brought into memory early so they will not need to be paged in when first accessed by the SAV processing. While results will vary, testing in the lab and by a few customers have shown some dramatic improvements – up to 60% faster save times in some cases. The performance gain seen is dependent on the directory structure, number and size of objects saved, amount of memory available, and the system configuration. This enhancement is available on both the SAV command and QsrSave() API.
To use this new function, you will need to install necessary the PTFs:
7.1 PTF information:
- SI44688 Save/Restore PTF with new function added.
- SI45792 Supersedes SI44688 and contains additional SAV performance improvements.
- SI44710 BRMS PTF that supports ASYNCBRING.
6.1 PTF information:
- SI44739 Save/Restore PTF with new function added.
- SI45791 Supersedes SI44739 and contains additional SAV performance improvements.
- SI44709 BRMS PTF that supports ASYNCBRING.
The BRMS product website also has additional information on this support under the topic Specify ASYNCBRING to improve performance of IFS backups and describes how you can use this support with BRMS.
One final note – the best performance improvement may be seen with a well-balanced directory tree in which all objects qualify for the save. In situations where a large number of objects reside in a single directory, few objects qualify for the save, or the system is memory constrained, performance may degrade with ASYNCBRING(*YES) specified.
I’d like to thank Jerry Simon from the Save/Restore team and David Bhaskaran from the BRMS team for their assistance in creating this blog article.
This blog post was edited on February 17, 2020 to fix broken links.
This blog post was originally published on IBMSystemsMag.com and is reproduced here by permission of IBM Systems Media.