The kernel writes workload statistics with each transaction step into buffers. This buffered data is then saved to stat files in AL11 directory DIR_DATA /usr/sap/<SID>/DVEBMGSxx/data (parameter stat/file). The files are named stat.DATxxx. When you run transaction STAD, it is reading from these files.
astat files (as opposed to stat files) are application statistics. Application stats are only created if it is setup in the application itself to create the stats. Many systems do not create these. System stats (stat files) on the other hand are always created at each step by the kernel.
You can deactivate the statistics by setting parameter stat/level = 0 (default is 1). You can do the same for application stats with stat/as_level = 0
stat/max_files determines how many stat files are kept and therefore how long the STAD data is retained. The maximum is 99 hours. See the following link:
http://scn.sap.com/community/netweaver-administrator/blog/2015/01/23/stad-retention-period
Related notes:
- 1927118 - STAT Files Grow Too Large
- 6833 - Deleting statistics file, size of statistics file
- 16513 - File system is full - what do I do?
More information and troubleshooting guides (including this one) on the BC-CCM-MON area are available in the CCMS Wiki space at:
Computing Center Management System (CCMS) - Technology Troubleshooting Guide - SCN Wiki
