Here at PARSEC Group, we often instigate or participate in VMS system performance analysis and capacity planning, and the data gathering tool we reach for, or recommend to our customers, is the free T4 (“Total Timeline Tracking Tool”) which was written by members of the original DEC VMS Engineering Team. This toolkit is provided free of charge
T4 is currently available through HPE here:
See OpenVMS Technical Journals online for a list of all of these valuable documents online.
Wayne Sauer, PARSEC founder and VMS internals expert, has written extensively about using T4 for VMS performance analysis, and has given many DECUS and technical conference presentations – here's a representative slide-deck:
And here's a great presentation by Keith W Hare, JCC Consulting Inc., about using T4 for gathering Oracle/Rdb performance data: