- z/OS file structures
- DFSMS on z/OS
- Data Class
- Management Class
- Storage Class
- Storage Group
- ACS routines
- z/OS performance
- z/OS file utilities
- z/OS SMF statistics
- z/OS RMF reporting
First a couple of historical EADM graphs that illustrate how storage performance has changed over the years.
Here's an example from 2010 of a customer who uses HDDs. You can see the effect of increased workloads during business hours, which almost doubles IO response times.
Example of performance report from 2015 of a customer who uses SSD and Flash with Tierring. Things have improved, but response times are still inconsistent.
Examples of EADM reports based on RMF file analysis. These reports run daily and provide information about z OS disk response times. As always the manufacturers say that the discs are fast but often this is not true. The customer can only know the truth if he analyzes with tools like EADM or equivalent. These are genuine customer reports, so the LPAR names are partially redacted to preserve confidentiality.
Disk response times - Peak hour Transaction processing over 1 month.
Disk response times - Day time Transaction processing over 1 month.
TAPE VTS / VSM / DLM repoonse times - Batch Transaction processing over 1 month.
APE VTS / VSM / DLM repoonse times - Combined processing over 1 month.
A 24 hours detailed analysis of response times over 7 LPARs. These are genuine customer reports, so the LPAR names are partially redacted to preserve confidentiality.
A 4 week analysis of TP response times.
4 week analysis of batch response times.
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