> Is there a reason not to use SHRDYNAMIC?

Open files are actually "files in use", so part of the file may be loaded in
the real memory, application
which uses this file may do some changes in that file directly in real
memory and then - at some later time -
physically save these chages to the disk, so with backing up open files you
may backup inconsistent, unusable
data.

Best regards

Leos Stehlik, IT Specialist
AIX, ADSM/TSM
IBM Czech republic