Re: Streaming Replication Networking Best Practices?

On Mon, May 14, 2018 at 3:33 PM, Peter Eisentraut <
peter(dot)eisentraut(at)2ndquadrant(dot)com> wrote:

> You might find that increasing the TCP receive buffer on the receiving
> side will help.
>

This got me wondering. I know Oracle requires minimums for some kernel
settings like net.core.rmem_default and rmem_max and similar for wmem, ie:

- net.core.rmem_default = 262144
- net.core.rmem_max = 4194304
- net.core.wmem_default = 262144
- net.core.wmem_max = 1048576

Looking at my primary and standby, they look to still be the CentOS
defaults for CentOS7 and CentOS6.

Primary (CentOS7)

- net.core.rmem_default = 212992
- net.core.rmem_max = 212992
- net.ipv4.tcp_rmem = 4096 87380 6291456
- net.core.wmem_default = 212992
- net.core.wmem_max = 212992
- net.ipv4.tcp_wmem = 4096 16384 4194304

Standby (CentOS6)

- net.core.rmem_default = 124928
- net.core.rmem_max = 124928
- net.ipv4.tcp_rmem = 4096 87380 4194304
- net.core.wmem_default = 124928
- net.core.wmem_max = 124928
- net.ipv4.tcp_wmem = 4096 16384 4194304

FWIW: these machines are VMWare with 8 cores and over 100GB of memory. I'm
assuming we have gigabit ethernet within the datacenter but the circuit
between the two is 200 Mbps.
--
Don Seiler
www.seiler.us