Hello All
Oracle Engine: 11.2.0.4 Enterprise Edition
OS: AIX 7
I have 3 instances running on one server.
Instance1
sga_max_size=5 GB
sga_target =0
memory_max_target = 5 GB
memory_target=5 GB
pga_aggregate_target =2 GB
Instance2
sga_max_size=110 GB
sga_target =0
memory_max_target = 110 GB
memory_target=100 GB
pga_aggregate_target =2 GB
Instance3
sga_max_size=24 GB
sga_target =0
memory_max_target = 24 GB
memory_target=24 GB
pga_aggregate_target =0
Note: Above values are taken from v$parameter view.
Server Physical Ram = 130GB
Server Paging Space = 20GB
Below is the output of command nmon
Memory ──────────────────────────────────────────────────────────────────────────────────────────────────────────────
│ Physical PageSpace | pages/sec In Out |FileSystemCache
│% Used 95.6% 1.0% | to Paging Space 0.0 0.0 | (numperm) 21.4%
│% Free 4.4% 99.0% | to File System 0.0 5.0 | Process 65.7%
│GB Used 124.2GB 0.2GB | Page Scans 0.0 | System 8.5%
│GB Free 5.8GB 19.8GB | Page Cycles 0.0 | Free 4.4%
│Total(GB) 130.0GB 20.0GB | Page Steals 0.0 | ------
│ | Page Faults 31.0 | Total 100.0%
│------------------------------------------------------------ | numclient 21.4%
│Min/Maxperm 6410MB( 5%) 115379MB( 90%) <--% of RAM | maxclient 90.0%
│Min/Maxfree 960 1088 Total Virtual 150.0GB | User 83.6%
│Min/Maxpgahead 2 8 Accessed Virtual 95.3GB 63.5%| Pinned 11.2%
We confirmed with Unix Admin that The Free paging space (free swap in AIX jargon) is near 100% all year, which means that the swap usage is almost zero.
So my question is can some one please explain to me how Oracle instances are configured for more memory than available, are working perfectly fine without using any swap space.?
Please let me know if any more detail is required.
Thanks