Configuring Congestion Settings in DRBD Proxy

This setting will help you tune your congestion policies for DRBD Proxy based replication.

Adjust the net{} section of the DRBD device's configuration as follows:

...  
  net {
    on-congestion pull-ahead;
    congestion-fill 200M;      # ~80% memlimit
    congestion-extents 1033;   # ~80% al-extents
    ...
    }
...

After adding those lines, you can adjust the DRBD device to load the settings:

# drbdadm adjust all -S; drbdadm adjust all

That will tell DRBD to temporarily pause replication, without breaking the connection, when it detects that 80% of the DRBD Proxy buffer is full OR when 80% of the al-extents have been marked dirty (more on that here: https://docs.linbit.com/docs/users-guide-8.4/#s-configure-congestion-policy)

 

Reviewed 2020/12/01 - DGT