Formatting VLF dump data

Use the IPCS VLFDATA subcommand to produce diagnostic reports about VLF. z/OS MVS IPCS Commands gives the syntax of the VLFDATA subcommand and z/OS MVS IPCS User's Guide explains how to use the VLFDATA option of the IPCS dialog.

The dump may also contain component trace data for VLF. See the component trace chapter of z/OS MVS Diagnosis: Tools and Service Aids for information on how to format this trace data.

VLFDATA divides the information about VLF into six reports. Each report corresponds to the following VLFDATA keywords listed in Table 1.

Table 1. Summary: VLFDATA keywords
Keyword	Report Displays:	See topic:
CLASS	Information about a VLF class.	VLFDATA CLASS subcommand output
EXCEPTION	Information about any inconsistencies found in the VLF data.	VLFDATA EXCEPTION subcommand output
STATS	Statistics on VLF activity	VLFDATA STATS subcommand output
STORAGE	Information about storage management of VLF data spaces sysplex.	VLFDATA STORAGE subcommand output
SUMMARY	Information about classes specified in the COFVLFxx parmlib member.	VLFDATA SUMMARY subcommand output
USER	Information relating to the non-VLF address space associated with the active task that was using a VLF function when VLF recovery received control.	VLFDATA USER subcommand output

Examples of VLFDATA reports follow. The order of the reports represent a typical sequence for diagnosing a VLF problem:

VLFDATA SUMMARY (or just VLFDATA)
VLFDATA EXCEPTION
VLFDATA USER
VLFDATA STATS
VLFDATA STORAGE
VLFDATA CLASS