Thanks for the responses.
We'll take this up with VMware support and then if it isn't a configuration issue, move it along to Redhat Linux support.
It was also useful to learn cgroups default support within the kernel can use up so much memory on a system with larger RAM. On the next reboot this will free up about 1.6 GB RAM. It might help with a little wiggle room until we know more about the other issue which seems to limit us to 1/2 our RAM.
On Mon, Dec 21, 2020 at 9:27 PM Tom Lane <tgl@xxxxxxxxxxxxx> wrote:
frank picabia <fpicabia@xxxxxxxxx> writes:
> My VMware admin has come back with a graph showing memory use over
> the period in question. He has looked over other indicators
> and there are no alarms triggered on the system.
> It jives with what Cacti reported. Memory was never exhausted
> and used only 50% of allocated RAM at the most.
> If it's not a configuration issue in Postgres, and both internal and
> external tools
> show memory was not consumed to the point of firing off the "cannot fork"
> error, would that mean that there is a bug in either the kernel or Postgres?
[ shrug... ] Postgres is just reporting to you that the kernel wouldn't
perform a fork(). Since you've gone to great lengths to show that
Postgres isn't consuming excessive resources, either this is a kernel bug
or you're running into some kernel-level (not Postgres) allocation limit.
I continue to suspect the latter. Desultory googling shows that VMware
can be configured to enforce resource allocation limits, so maybe you
should be taking a hard look at your VMware settings.
regards, tom lane
