[DRBD-user] slow i/o performance

[EDV at bauerfunken.de]

Hello all,

I'm getting problems with the performance of my drbd installation.

I'm using two servers with drbd 8.3.7 in primary/slave configuration installed on openfiler 2.3.

When I'm copying one file of 2GB directly on the drbd-device I'm getting an i/o of 13MB/s as maximum.

This drbd-device is also used as XEN-shared storage with 8 VM's on it. Now in normal usage the i/o of the
same testing gets 2.6MB/s.

I'm monitored the direct network connection for syncing both nodes and get 236MBit/s or 29.5MB/s
as maximum. This connection uses 2 1GBit network adaptors with crosslink-cable.

My configuration file drbd.conf

global {
 # minor-count 64;
 # dialog-refresh 5; # 5 seconds
 # disable-ip-verification;
 usage-count ask;
}

common {
 syncer { rate 100M; }
}

resource cluster_metadata {
 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 {
  after-sb-0pri disconnect;
  after-sb-1pri disconnect;
  after-sb-2pri disconnect;
  rr-conflict disconnect;
 }

 syncer {
  # rate 10M;
  # after "r2";
  al-extents 257;
 }

 on filer1 {
  device /dev/drbd0;
  disk /dev/sdc1;
  address 10.3.2.1:7788;
  meta-disk internal;
 }

 on filer2 {
  device /dev/drbd0;
  disk /dev/sdc1;
  address 10.3.2.2:7788;
  meta-disk internal;
 }
}

resource vg0drbd {
 protocol C;
 startup {
  wfc-timeout 0; ## Infinite!
  degr-wfc-timeout 120; ## 2 minutes.
 }

 disk {
  no-disk-flushes;
  on-io-error detach;
 }

 net {
  # timeout 60;
  # connect-int 10;
  # ping-int 10;
  # max-buffers 2048;
  # max-epoch-size 2048;
  sndbuf-size 0;
 }

 syncer {
  after "cluster_metadata";
 }

 on filer1 {
  device /dev/drbd1;
  disk /dev/sdc2;
  address 10.3.2.1:7789;
  meta-disk internal;
 }

 on filer2 {
  device /dev/drbd1;
  disk /dev/sdc2;
  address 10.3.2.2:7789;
  meta-disk internal;
 }
}

drbdsetup drbd1 show says:

disk {
      size              0s _is_default; # bytes
      on-io-error       detach;
      fencing           dont-care _is_default;
      no-disk-flushes ;
      max-bio-bvecs     0 _is_default;
}
net {
      timeout           60 _is_default; # 1/10 seconds
      max-epoch-size    2048 _is_default;
      max-buffers       2048 _is_default;
      unplug-watermark  128 _is_default;
      connect-int       10 _is_default; # seconds
      ping-int          10 _is_default; # seconds
      sndbuf-size       0 _is_default; # bytes
      rcvbuf-size       0 _is_default; # bytes
      ko-count          0 _is_default;
      after-sb-0pri     disconnect _is_default;
      after-sb-1pri     disconnect _is_default;
      after-sb-2pri     disconnect _is_default;
      rr-conflict       disconnect _is_default;
      ping-timeout      5 _is_default; # 1/10 seconds
}
syncer {
      rate              102400k; # bytes/second
      after             0;
      al-extents        127 _is_default;
}
protocol C;
_this_host {
      device                  minor 1;
      disk              "/dev/sdc2";
      meta-disk         internal;
      address                 ipv4 10.3.2.1:7789;
}
_remote_host {
      address                 ipv4 10.3.2.2:7789;
}

Under my volume drbd1 I'm using a RAID5-system with an Adaptec AAC-RAID
controller and 1.8TB disc-capacity.

Can anyone help me to increase the i/o performance ?

Best regards

Andreas Weigand

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