[DRBD-user] drbd performance tuning

[Christoph Langbein]

Hello,
I've setup two debian etch systems with drbd, running vmware images on
this partitions. I'm trying to speedup write performance (and maybe
overall performance;)).
I've setup my network using this values in /etc/sysctl.conf:
----------------
# increase TCP max buffer size setable using setsockopt()
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
# increase Linux autotuning TCP buffer limits
# min, default, and max number of bytes to use
# set max to at least 4MB, or higher if you use very high BDP paths
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216

# don't cache ssthresh from previous connection
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_moderate_rcvbuf = 1
# recommended to increase this for 1000 BT or higher
net.core.netdev_max_backlog = 2500
----------------
Using Asus P5KC I've GBit Ethernet and issue ifconfig eth1 txqueuelen
1000 when my drbd ethernet device (eth1) comes up.
eth1 is only used to sync drbd.


My drbd.conf is:
-----------------------------------
global {
    usage-count no;
}

common {
  syncer { rate 100M; }
}
resource vmware {
  protocol C;
  handlers {
    pri-on-incon-degr "echo o > /proc/sysrq-trigger ; halt -f";
    pri-lost-after-sb "echo o > /proc/sysrq-trigger ; halt -f";
    local-io-error "echo o > /proc/sysrq-trigger ; halt -f";
    outdate-peer "/usr/sbin/drbd-peer-outdater";
  }

  startup {
    wfc-timeout  0;
    degr-wfc-timeout 120;    # 2 minutes.
  }

  disk {
    on-io-error   detach;
  }

  net {
    max-buffers     8192;
  }

  syncer {
    rate 100M;
    al-extents 257;
  }

  on test1 {
    device     /dev/drbd1;
    disk       /dev/sdb1;
    address    10.10.10.170:7789;
    flexible-meta-disk  internal;
  }

  on test2 {
    device    /dev/drbd1;
    disk      /dev/sda1;
    address   10.10.10.180:7789;
    meta-disk internal;
  }
}
-----------------------------------------
Can someone explain me how to speedup this setup (Maybe using
JumboFrames on this interfaces) and if it would speedup my system when I
use an external metadisk ? I've seen setups where metadisk is something
like /dev/sda1[1] but I'm not sure what this means.

Thanks in advance
Christoph