Improving the performance of the logon process

You should review the performance of the logon process, and, if necessary, adjust the factors that affect logon performance. The following are some guidelines for improving the performance of the logon process:
  • Shorten logon procedures by allocating as few data sets as possible. However, note that allocating data sets in a logon procedure may improve on-line performance, after a user has logged on. For more information, see Defining data sets in a logon procedure.
  • Avoid the use of STEPLIBs in logon JCL.
  • Reduce the amount of searching the system does to locate a logon procedure:
    • Rename or move logon procedures so they are at the beginning of the procedure library or at the beginning of the library concatenation.
    • If you are using JES3, specify commonly-used logon procedures in a BLDL list. To specify a BLDL list, use the JES3 PROC initialization statement. For more information about using the JES3 PROC initialization statement, see z/OS JES3 Initialization and Tuning Guide.
  • Place logon procedures in a procedure library that is likely to be open when a user logs on. For example, if possible, place all your procedures—both those for batch and for on-line—in the same procedure library.
  • Allow users to reconnect after being disconnected (thus bypassing the logon process). Use SYS1.PARMLIB member TSOKEYxx to extend the amount of time address spaces remain active after users have been disconnected. One problem with extending the amount of time is that it can allow users to tie up logons. For more information, see Customizing the reconnect option of the LOGON command.
  • Bypass or reduce the use of the broadcast data set. You can:
    • Use individual user log data sets to store messages sent to individual users.
    • Limit the use of the OPERATOR SEND command at your installation.
    • Have users bypass the use of the broadcast data set by using the NONOTICES and NOMAIL parameters of the LOGON command. For more information about using the LOGON command, see z/OS TSO/E Command Reference.
    • Use the SYSPLEXSHR option of the SEND PARMLIB parameter to avoid I/O to the broadcast data set for the display of system notices. For more information, see Broadcast data set in a sysplex.