#
# drbd.conf example
#
# parameters you _need_ to change are the hostname, device, disk,
# meta-disk, address and port in the "on <hostname> {}" sections.
#
# you ought to know about the protocol, and the various timeouts.
#
# you probably want to set the rate in the syncer sections
#
# increase timeout and maybe ping-int in net{}, if you see
# problems with "connection lost/connection established"
# (or change your setup to reduce network latency; make sure full
#  duplex behaves as such; check average roundtrip times while
#  network is saturated; and so on ...)
#

#
# Upgrading from DRBD-0.6.x
#
# Using the size parameter in the disk section (was disk-size) is
# no longer valid. The agreed disk size is now stored
# in DRBD's non volatile meta data files.
#
# NOTE that if you do not have some dedicated partition to use for
# the meta-data, you may use 'internal' meta-data.
#
#	THIS HOWEVER WILL DESTROY THE LAST 128M
#	OF THE LOWER LEVEL DEVICE.
#
# So you better make sure you shrink the filesystem by 128M FIRST!
# or by 132M just to be sure... :)
#

skip {
  As you can see, you can also comment chunks of text
  with a 'skip[optional nonsense]{ skipped text }' section.
  This comes in handy, if you just want to comment out
  some 'resource <some name> {...}' section:
  just precede it with 'skip'.

  The basic format of option assignment is
  <option name><linear whitespace><value>;
  
  It should be obvious from the examples below,
  but if you really care to know the details:
  
  <option name> :=
        valid options in the respective scope
  <value>  := <num>|<string>|<choice>|...
              depending on the set of allowed values
              for the respective option.
  <num>    := [0-9]+, sometimes with an optional suffix of K,M,G
  <string> := (<name>|\"([^\"\\\n]*|\\.)*\")+
  <name>   := [/_.A-Za-z0-9-]+
}

#
# At most ONE global section is allowed.
# It must precede any resource section.
#
# global {
    # use this if you want to define more resources later
    # without reloading the module.
    # by default we load the module with exactly as many devices
    # as configured mentioned in this file.
    #
    # minor-count 5;

    # The user dialog counts and displays the seconds it waited so
    # far. You might want to disable this if you have the console 
    # of your server connected to a serial terminal server with
    # limited logging capacity.
    # The Dialog will print the count each 'dialog-refresh' seconds,
    # set it to 0 to disable redrawing completely. [ default = 1 ]
    #
    # dialog-refresh 5; # 5 seconds

    # this is for people who set up a drbd device via the
    # loopback network interface or between two VMs on the same
    # box, for testing/simulating/presentation
    # otherwise it could trigger a run_tasq_queue deadlock.
    # I'm not sure whether this deadlock can happen with two
    # nodes, but it seems at least extremely unlikely; and since
    # the io_hints boost performance, keep them enabled.
    #
    # With linux 2.6 it no longer makes sense.
    # So this option should vanish.	--lge
    #
    # disable-io-hints;
# }

#
# this need not be r#, you may use phony resource names,
# like "resource web" or "resource mail", too
#

resource r0 {

  # transfer protocol to use.
  # C: write IO is reported as completed, if we know it has
  #    reached _both_ local and remote DISK.
  #    * for critical transactional data.
  # B: write IO is reported as completed, if it has reached
  #    local DISK and remote buffer cache.
  #    * for most cases.
  # A: write IO is reported as completed, if it has reached
  #    local DISK and local tcp send buffer. (see also sndbuf-size)
  #    * for high latency networks
  #
  #**********
  # uhm, benchmarks have shown that C is actually better than B.
  # this note shall disappear, when we are convinced that B is
  # the right choice "for most cases".
  # Until then, always use C unless you have a reason not to.
  #	--lge
  #**********
  #
  protocol C;

  # what should be done in case the cluster starts up in
  # degraded mode, but knows it has inconsistent data.
  incon-degr-cmd "echo '!DRBD! pri on incon-degr' | wall ; sleep 60 ; halt -f";

  startup {
    # Wait for connection timeout. 
    # The init script blocks the boot process until the resources
    # are connected. This is so when the cluster manager starts later,
    # it does not see a resource with internal split-brain.
    # In case you want to limit the wait time, do it here.
    # Default is 0, which means unlimited. Unit is seconds.
    #
    # wfc-timeout  0;

    # Wait for connection timeout if this node was a degraded cluster.
    # In case a degraded cluster (= cluster with only one node left)
    # is rebooted, this timeout value is used. 
    #
    degr-wfc-timeout 120;    # 2 minutes.
  }

  disk {
    # if the lower level device reports io-error you have the choice of
    #  "pass_on"  ->  Report the io-error to the upper layers.
    #                 Primary   -> report it to the mounted file system.
    #                 Secondary -> ignore it.
    #  "panic"    ->  The node leaves the cluster by doing a kernel panic.
    #  "detach"   ->  The node drops its backing storage device, and
    #                 continues in disk less mode.
    #
    on-io-error   detach;
  }

  net {
    # this is the size of the tcp socket send buffer
    # increase it _carefully_ if you want to use protocol A over a
    # high latency network with reasonable write throughput.
    # defaults to 2*65535; you might try even 1M, but if your kernel or
    # network driver chokes on that, you have been warned.
    # sndbuf-size 512k;

    # timeout       60;    #  6 seconds  (unit = 0.1 seconds)
    # connect-int   10;    # 10 seconds  (unit = 1 second)
    # ping-int      10;    # 10 seconds  (unit = 1 second)

    # Maximal number of requests (4K) to be allocated by DRBD.
    # The minimum is hardcoded to 32 (=128 kb).
    # For hight performance installations it might help if you
    # increase that number. These buffers are used to hold
    # datablocks while they are written to disk.
    #
    # max-buffers     2048;

    # The highest number of data blocks between two write barriers. 
    # If you set this < 10 you might decrease your performance.
    # max-epoch-size  2048;

    # if some block send times out this many times, the peer is 
    # considered dead, even if it still answers ping requests.
    # ko-count 4;

    # if the connection to the peer is lost you have the choice of
    #  "reconnect"   -> Try to reconnect (AKA WFConnection state)
    #  "stand_alone" -> Do not reconnect (AKA StandAlone state)
    #  "freeze_io"   -> Try to reconnect but freeze all IO until
    #                   the connection is established again.
    # on-disconnect reconnect;

  }

  syncer {
    # Limit the bandwith used by the resynchronisation process.
    # default unit is KB/sec; optional suffixes K,M,G are allowed
    #
    rate 10M;

    # All devices in one group are resynchronized parallel. 
    # Resychronisation of groups is serialized in ascending order. 
    # Put DRBD resources which are on different physical disks in one group.
    # Put DRBD resources on one physical disk in different groups.
    #
    group 1;

    # Configures the size of the active set. Each extent is 4M, 
    # 257 Extents ~> 1GB active set size. In case your syncer
    # runs @ 10MB/sec, all resync after a primary's crash will last
    # 1GB / ( 10MB/sec ) ~ 102 seconds ~ One Minute and 42 Seconds.
    # BTW, the hash algorithm works best if the number of al-extents
    # is prime. (To test the worst case performace use a power of 2)
    al-extents 257;
  }

  on amd {
    device     /dev/drbd0;
    disk       /dev/hde5;
    address    192.168.22.11:7788;
    meta-disk  internal;

    # meta-disk is either 'internal' or '/dev/ice/name [idx]'
    #
    # You can use a single block device to store meta-data
    # of multiple DRBD's.
    # E.g. use meta-disk /dev/hde6[0]; and meta-disk /dev/hde6[1];
    # for two different resources. In this case the meta-disk
    # would need to be at least 256 MB in size.
    #
    # 'internal' means, that the last 128 MB of the lower device
    # are used to store the meta-data.
    # You must not give an index with 'internal'.
  }

  on alf {
    device    /dev/drbd0;
    disk      /dev/hdc5;
    address   192.168.22.12:7788;
    meta-disk internal;
  }
}

#
# yes, you may also quote the resource name.
# but don't include whitespace, unless you mean it :)
#
resource "r1" {
  protocol C;
  incon-degr-cmd "echo '!DRBD! pri on incon-degr' | wall ; sleep 60 ; halt -f";
  startup {
    wfc-timeout         0;  ## Infinite!
    degr-wfc-timeout  120;  ## 2 minutes.
  }
  disk {
    on-io-error detach;
  }
  net {
    # timeout           60;
    # connect-int       10;
    # ping-int          10;
    # max-buffers     2048;
    # max-epoch-size  2048;
  }
  syncer {
    rate   4M;
    group   1; # sync concurrently with r0
  }

  on amd {
    device	/dev/drbd1;
    disk	/dev/hde6;
    address	192.168.22.11:7789;
    meta-disk	/dev/somewhere [7];
  }

  on alf {
    device     /dev/drbd1;
    disk       /dev/hdc6;
    address    192.168.22.12:7789;
    meta-disk  /dev/somewhere [7];
  }
}

resource r2 {
  protocol C;
  incon-degr-cmd "echo '!DRBD! pri on incon-degr' | wall ; sleep 60 ; halt -f";

  startup { wfc-timeout 0; degr-wfc-timeout 120; }
  disk    { on-io-error detach; }
  net     { timeout 60; connect-int 10; ping-int 10;
            max-buffers 2048; max-epoch-size 2048; }
  syncer  { rate 4M; group 2; } # sync when r0 and r1 are finished syncing.
  on amd {
    address 192.168.22.11:7790;
    disk /dev/hde7; device /dev/drbd2; meta-disk "internal";
  }
  on alf {
    device "/dev/drbd2"; disk "/dev/hdc7"; meta-disk "internal";
    address 192.168.22.12:7790;
  }
}

resource r3 {
  protocol	C;
  incon-degr-cmd "echo '!DRBD! pri on incon-degr' | wall ; sleep 60 ; halt -f";
  startup { wfc-timeout	0; degr-wfc-timeout	120; }
  disk { on-io-error detach; }
  syncer {
    rate	4M;
    group	3;   # sync when r2 is finished syncing.
  }
  on amd {
    device	/dev/drbd3;
    disk	/dev/hde8;
    address	192.168.22.11:7791;
    meta-disk	internal;
  }
  on alf {
    device	/dev/drbd3;
    disk	/dev/hdc8;
    address	192.168.22.12:7791;
    meta-disk	/some/where[8];
  }
}
