Tweaked DRBD

resource ems-store-01 {
    startup {
      become-primary-on both;
    }
    net {
      protocol C;
      allow-two-primaries yes;
      verify-alg sha1;
      data-integrity-alg sha1;
      csums-alg md5;

      connect-int 20;
      ping-int 15;
      timeout 100;
      cram-hmac-alg sha1;
      shared-secret passw0rd;

      max-buffers 8000;
      max-epoch-size 8000;

      after-sb-0pri discard-zero-changes;
      after-sb-1pri consensus;
      after-sb-2pri disconnect;
    }
    disk {
      on-io-error pass_on;
      fencing dont-care;
      al-extents 6000;
    }
    ...
}

scheduler = deadline, front_merges = 0, read_expire = 150, write_expire = 1500