[DRBD-user] drbd9 protocol A on-congestion pull-ahead

[Den]

Hello,
I'm working in performance tuning with protocol A over a 500 Mb/s link

I set up on-congestion pull-ahead, congestion-fill and congestion-extents
During intensive write, the 500Mb/s link is the limit and the 
replication is not detached.

My configuration is below, please give me some suggestions or if I 
missed something

Thank you

----------------------------------------------------------------

cat /proc/drbd
version: 9.0.12-1 (api:2/proto:86-112)
GIT-hash: 7eb4aef4abbfba8ebb1afbcc30574df74db0063e build by root at int1, 
2018-03-18 16:38:45
Transports (api:16): tcp (9.0.12-1)

drbdmanage net-options --protocol A --sites 'farm1:ext1'
drbdmanage net-options --max-buffers 20000 --sites 'farm1:ext1'
drbdmanage net-options --max-epoch-size 20000 --sites 'farm1:ext1'
drbdmanage net-options --sndbuf-size 10485760 --sites 'farm1:ext1'
drbdmanage net-options --on-congestion pull-ahead --sites 'farm1:ext1'
drbdmanage net-options --congestion-fill 524288 --sites 'farm1:ext1'
drbdmanage net-options --congestion-extents 1024 --sites 'farm1:ext1'
drbdmanage disk-options --al-extents 2048 --common
drbdmanage net-options --on-congestion pull-ahead --sites 'farm1:ext1'


cat /var/lib/drbd.d/drbdmanage_global_common.conf
common {
    disk {
        al-extents 2048;
    }
}


cat /var/lib/drbd.d/drbdmanage_vm-101-disk-1.res
resource vm-101-disk-1 {
template-file "/var/lib/drbd.d/drbdmanage_global_common.conf";

    net {
        allow-two-primaries yes;
        cram-hmac-alg sha1;
    }
    connection {
       host int1;
       host ext1;
       net {
          max-epoch-size 20000;
          protocol A;
          max-buffers 20000;
          allow-two-primaries no;
          congestion-extents 1024;
          on-congestion pull-ahead;
          sndbuf-size 10485760;
          congestion-fill 524288;
       }
    }
     on int1 {
         node-id 1;
         volume 0 {
             device minor 105;
             disk /dev/drbdpool/vm-101-disk-1_00;
             disk {
                 size 52428800k;
             }
             meta-disk internal;
         }
     }
     on ext1 {
         node-id 0;
         volume 0 {
             device minor 105;
             disk /dev/drbdpool/vm-101-disk-1_00;
             disk {
                 size 52428800k;
             }
             meta-disk internal;
         }
     }
}