Re: Server is swapping with free memory available
- From: niall.litchfield@xxxxxxxxx
- To: nupendra@xxxxxxxxxxx
- Date: Wed, 20 Mar 2019 07:52:10 +0000
HI Upendra
On Wed, Mar 20, 2019 at 2:51 AM Upendra nerilla <nupendra@xxxxxxxxxxx>
wrote:
- disk_asynch_io = true
As I think someone else pointed out if you don't use direct IO then the
datafiles will be cached in the FS cache as well as the database blocks
being cached in the buffer cache. It's fairly unlikely that this will be as
effective as direct IO, especially on a server with multiple databases on
it. Certainly though, so long as the total size of all the databases is
larger than the filesystem cache you will get the swapping you observe.
- We aren't currently using HUGEPAGES, I would like to configure them,
but wanted to get this issue fixed before moving into that direction
You have two very large SGAs. I suggest you run grep PageTables
/proc/meminfo to see how much memory is being used by them. I suspect you
will be surprised, assuming you have several hundred sessions for each
database - which doesn't look unreasonable to assume with such large SGAs
then I expect tens of GB of PageTable entries. .
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