The ConstrainedSHMSizeMB="size in megabytes" will restrict memory to the "size in megabytes".  The PercentAvailSysResources may also be used if partition servers are used (refer to the document titled "How Does the NOTES.INI Parameter PercentAvailSysResources Work?" [#189489] for additional information).  All of these notes.ini values interact. The following is an explanation:
On AIX (a segmented memory platform) Domino takes the lower of :
- "Mappable shared memory size dynamic from maxdata"
- "ram on the system * (PercentAvailSysResources/100)"
- "Notes.ini ConstrainedSHMSizeMB" and "ConstrainedSHM"
   
It should be noted that ConstrainedSHMSizeMB will round down on AIX only to a 256 megabyte boundary.
Example:  if set to 1700, the size will be set to 1536.  On all other platforms, Domino will size its shared memory usage within the limits derived above.