I don't know if this is an issue but it has my system administrator concerned. We just recently switched our production database from an HP-UX server to a Red Hat Linux server and the normal output of glance has changed. When I started the database on HP-UX, glance would report the Memory usage commensurate with the memory_target parameter in the spfile. For example, HP server has 64G of RAM and memory target in spfile is 28G. As soon as I start database, glance reports Memory usage as moving from around 10% to up over 50%.
However, on Linux, server has 128G of RAM and memory target in spfile is 42G. When I start Oracle, glance reports memory usage as moving from 3% to 8%. Database has been running for a couple of days and memory usage has not gone higher than 11% according to glance.
Does HP grab more memory up front where Linux only grabs memory when it needs it? Does Glance operate differently between the two operating systems?
HP-UX is B.11.31 ia64
Red Hat is Release 6 x86_64