Enterprise Linux: DRAM usage is not optimal
SergeyBJun 18 2007 — edited Jun 19 2007I've installed Enterprise Linux (Release 4 Update 5) and Oracle Database 10gR2. After a while I noticed odd thing, that it's never been used more than ~900 Mb out of 2Gb dram. There are several Oracle instances with ~350 Mb SGA and one with 1G SGA. Instead of using free memory the swap space is being used and high swapping activity is observed.
The output of "free" command:
total used free shared buffers cached
Mem: 2074920 2042208 32712 0 5864 1281372
-/+ buffers/cache: 754972 1319948
Swap: 2097112 1155988 941124
I've discovered on some Linux forums, that it's a old Red Hat problem (or bug) and with new kernels there are parameters which can cure this: vm.swappiness and vm.vfs_cache_pressure.
I set them up as follows:
vm.swappiness=5
vm.vfs_cache_pressure=10000000
It’s slightly improved performance, but the whole picture hasn’t changed.
Could somebody help me?