Re: linux memory settings on OL 6.2 ( red hat compatible )

# You are smart. Transparent huge pages mechanism is still in its infancy. I have the same thing in my rc.local script. Speaking of sys, you should also enable deadline scheduler for the disks that will be used by Oracle:

Ummm ... not so smart ... found it and set it after problems ... looks like a "nifty" new default behavior in 6.2 red hat compatible kernel that is buggy.

>
> echo deadline >/sys/block/sdb/queue/scheduler
>
> Substitute your own devices for "sdb".

Does that make any sense for EMC powerpath LUNS?

Only using EMC LUNs and everything runs via ASM.

# With such a large memory, you don't want to throw out inodes and directory entries quickly. I would set something like vm.vfs_cache_pressure = 20 to retain them as long as possible.

Well we don't have anything on any file systems really ... everything cached in database buffer cache.

# The "pagecache" parameter is obsolete and should be omitted.

Yeah I was looking around for it in the /proc but not finding it ... wondering ... still so many people recommending setting it ... but using it does not seem to have any effect ... so you must be right here.

# You should use dirty_* parameters instead. Also, you want to set page-cluster to 5. That will cause swapper to try swapping out chunks of 32 (2**5) pages in a single IO operation, if possible. I would also set overcommit_memory to 1, to prevent OOM killer from activating.

Will think about those thanks. Received on Sat Sep 08 2012 - 20:23:15 CDT