#
# At most ONE global section is allowed.
# It must precede any resource section.
#
global {
    # By default we load the module with a minor-count of 32. In case you
    # have more devices in your config, the module gets loaded with
    # a minor-count that ensures that you have 10 minors spare.
    # In case 10 spare minors are too little for you, you can set the
    # minor-count exeplicit here. ( Note, in contrast to DRBD-0.7 an
    # unused, spare minor has only a very little overhead of allocated
    # memory (a single pointer to be exact). )
    #
    # minor-count 64;

    # 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

    # You might disable one of drbdadm's sanity check.
    # disable-ip-verification;

    # Participate in DRBD's online usage counter at http://usage.drbd.org
    # possilbe options: ask, yes, no. Default is ask. In case you do not
    # know, set it to ask, and follow the on screen instructions later.
    usage-count yes;
}


#
# The common section can have all the sections a resource can have but
# not the host section (started with the "on" keyword).
# The common section must precede all resources.
# All resources inherit the settings from the common section.
# Whereas settings in the resources have precedence over the common
# setting.
#

common {
  syncer { rate 10M; }
#这个值在后面的资源中也可以设置

}

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

resource r0 {
#这里定义了一个资源，drbd环境中可以有多个资源，比如我们可以定义apach、smb等
#资源，在初始化的时候需要根据这个资源名创建一个记录文件，后面会用到这个资源名。
  # 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;
#是上面描述三种drbd的协议，通常默认为C就行了
  handlers {
    # what should be done in case the node is primary, degraded
    # (=no connection) and has inconsistent data.
    pri-on-incon-degr "echo o > /proc/sysrq-trigger ; halt -f";

    # The node is currently primary, but lost the after split brain
    # auto recovery procedure. As as consequence it should go away.
    pri-lost-after-sb "echo o > /proc/sysrq-trigger ; halt -f";

    # In case you have set the on-io-error option to "call-local-io-error",
    # this script will get executed in case of a local IO error. It is
    # expected that this script will case a immediate failover in the
    # cluster.
    local-io-error "echo o > /proc/sysrq-trigger ; halt -f";

    # Commands to run in case we need to downgrade the peer's disk
    # state to "Outdated". Should be implemented by the superior
    # communication possibilities of our cluster manager.
    # The provided script uses ssh, and is for demonstration/development
    # purposis.
    # outdate-peer "/usr/lib/drbd/outdate-peer.sh on amd 192.168.22.11 192.168.23.11 on alf 192.168.22.12 192.168.23.12";
    #
    # Update: Now there is a solution that relies on heartbeat's
    # communication layers. You should really use this.
    outdate-peer "/usr/sbin/drbd-peer-outdater";

    # The node is currently primary, but should become sync target
    # after the negotiating phase. Alert someone about this incident.
    #pri-lost "echo pri-lost. Have a look at the log files. | mail -s 'DRBD Alert' root";

    # Notify someone in case DRBD split brained. 
    #split-brain "echo split-brain. drbdadm -- --discard-my-data connect $DRBD_RESOURCE ? | mail -s 'DRBD Alert' root";
  }

  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;
#这个值用来控制两个节点启动的时候等待对方的最长时间，如果设置为0，那么当一
#个节点启动时另一个节点没有起来或者出现了网络故障，那么这个节点将无限的等待
#对方起来	

    # 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.

    # In case there was a split brain situation the devices will
    # drop their network configuration instead of connecting. Since
    # this means that the network is working, the cluster manager
    # should be able to communicate as well. Therefore the default
    # of DRBD's init script is to terminate in this case. To make
    # it to continue waiting in this case set this option.
    # 
    # wait-after-sb;

    # In case you are using DRBD for GFS/OCFS2 you want that the
    # startup script promotes it to primary. Nodenames are also
    # possible instead of "both".
    # become-primary-on both;
  }

  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.
    #  "call-local-io-error"
    #	          ->  Call the script configured by the name "local-io-error".
    #  "detach"   ->  The node drops its backing storage device, and
    #                 continues in disk less mode.
    #
    on-io-error   detach;

    # Controls the fencing policy, default is "dont-care". Before you
    # set any policy you need to make sure that you have a working
    # outdate-peer handler. Possible values are:
    #  "dont-care"     -> Never call the outdate-peer handler. [ DEFAULT ]
    #  "resource-only" -> Call the outdate-peer handler if we primary and
    #			  loose the connection to the secondary. As well
    #			  whenn a unconnected secondary wants to become
    #			  primary.
    #  "resource-and-stonith"
    #                  -> Calls the outdate-peer handler and freezes local
    #                     IO immediately after loss of connection. This is
    #			  necessary if your heartbeat can STONITH the other
    #                     node.
    # fencing resource-only;

    # In case you only want to use a fraction of the available space
    # you might use the "size" option here.
    #
    # size 10G;
  }

  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)
    # ping-timeout   5;    # 500 ms (unit = 0.1 seconds)

    # Maximal number of requests (4K) to be allocated by DRBD.
    # The minimum is hardcoded to 32 (=128 kByte).
    # For high 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;

    # When the number of outstanding requests on a standby (secondary)
    # node exceeds bdev-threshold, we start to kick the backing device
    # to start its request processing. This is an advanced tuning
    # parameter to get more performance out of capable storage controlers.
    # Some controlers like to be kicked often, other controlers
    # deliver better performance when they are kicked less frequently.
    # Set it to the value of max-buffers to get the least possible
    # number of run_task_queue_disk() / q->unplug_fn(q) calls.
    #
    # unplug-watermark   128;


    # 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 you want to use OCFS2/openGFS on top of DRBD enable
    # this optione, and only enable it if you are going to use
    # one of these filesystems. Do not enable it for ext2,
    # ext3,reiserFS,XFS,JFS etc...
    # allow-two-primaries;

    # This enables peer authentication. Without this everybody
    # on the network could connect to one of your DRBD nodes with
    # a program that emulates DRBD's protocoll and could suck off
    # all your data.
    # Specify one of the kernel's digest algorithms, e.g.:
    # md5, sha1, sha256, sha512, wp256, wp384, wp512, michael_mic ...
    # an a shared secret.
    # Authentication is only done once after the TCP connection
    # is establised, there are no disadvantages from using authentication,
    # therefore I suggest to enable it in any case.
    # cram-hmac-alg "sha1";
    # shared-secret "FooFunFactory";

    # In case the nodes of your cluster nodes see each other again, after
    # an split brain situation in which both nodes where primary
    # at the same time, you have two diverged versions of your data.
    #
    # In case both nodes are secondary you can control DRBD's
    # auto recovery strategy by the "after-sb-0pri" options. The
    # default is to disconnect.
    #    "disconnect" ... No automatic resynchronisation, simply disconnect.
    #    "discard-younger-primary"
    #                     Auto sync from the node that was primary before
    #                     the split brain situation happened.
    #    "discard-older-primary"
    #                     Auto sync from the node that became primary
    #                     as second during the split brain situation.
    #    "discard-least-changes"
    #                     Auto sync from the node that touched more
    #                     blocks during the split brain situation.
    #    "discard-node-NODENAME"
    #                     Auto sync _to_ the named node.
    after-sb-0pri disconnect;

    # In one of the nodes is already primary, then the auto-recovery
    # strategie is controled by the "after-sb-1pri" options.
    #    "disconnect" ... always disconnect
    #    "consensus"  ... discard the version of the secondary if the outcome
    #                     of the "after-sb-0pri" algorithm would also destroy
    #                     the current secondary's data. Otherwise disconnect.
    #    "violently-as0p" Always take the decission of the "after-sb-0pri"
    #                     algorithm. Even if that causes case an erratic change
    #		          of the primarie's view of the data.
    #                     This is only usefull if you use an 1node FS (i.e.
    #		          not OCFS2 or GFS) with the allow-two-primaries
    #		          flag, _AND_ you really know what you are doing.
    #		          This is DANGEROUS and MAY CRASH YOUR MACHINE if you
    #		          have a FS mounted on the primary node.
    #    "discard-secondary"
    #                     discard the version of the secondary.
    #    "call-pri-lost-after-sb"  Always honour the outcome of the "after-sb-0pri"
    #                     algorithm. In case it decides the the current
    #                     secondary has the right data, it panics the
    #                     current primary.
    #    "suspend-primary" ???
    after-sb-1pri disconnect;

    # In case both nodes are primary you control DRBD's strategy by
    # the "after-sb-2pri" option.
    #    "disconnect" ... Go to StandAlone mode on both sides.
    #    "violently-as0p" Always take the decission of the "after-sb-0pri".
    #    "call-pri-lost-after-sb" ... Honor the outcome of the "after-sb-0pri"
    #                     algorithm and panic the other node.

    after-sb-2pri disconnect;

    # To solve the cases when the outcome of the resync descissions is
    # incompatible to the current role asignment in the cluster.
    #    "disconnect" ... No automatic resynchronisation, simply disconnect.
    #    "violently" .... Sync to the primary node is allowed, violating the
    #	                  assumption that data on a block device is stable
    #		          for one of the nodes. DANGEROUS, DO NOT USE.
    #    "call-pri-lost"  Call the "pri-lost" helper program on one of the
    #	                  machines. This program is expected to reboot the
    #                     machine. (I.e. make it secondary.)
    rr-conflict disconnect;

    # DRBD-0.7's behaviour is equivalent to
    #   after-sb-0pri discard-younger-primary;
    #   after-sb-1pri consensus;
    #   after-sb-2pri disconnect;

    # DRBD can ensure the data integrity of the user's data on the network
    # by comparing hash values. 
    # Note: Normally this is ensured by the 16 bit checksums in the headers 
    # of TCP/IP packets. Unforunately it turned out that GBit NICs with 
    # various offloading engines might produce valid checksums for corrupted 
    # data. Use this option during your pre-production tests, usually you
    # want to turn it off for production to reduce CPU overhead.
    # data-integrity-alg "md5";
  }

  syncer {
    # Limit the bandwith used by the resynchronisation process.
    # default unit is kByte/sec; optional suffixes K,M,G are allowed.
    #
    # Even though this is a network setting, the units are based
    # on _byte_ (octet for our french friends) not bit.
    # We are storage guys.
    #
    # Note that on 100Mbit ethernet, you cannot expect more than
    # 12.5 MByte total transfer rate.
    # Consider using GigaBit Ethernet.
    #
rate 10M;
#设置drbd在同步数据过程中的最高速率，这里设置的为10M，表示是上限，如果网络#环境不能达到这个传输速率，那么它将以网络的的最高速率传输数据，如果网络环境
#的传输速率超过了10M，那么drbd将限制10M为传输速率。

    # Normally all devices are resynchronized parallel.
    # To achieve better resynchronisation performance you should resync
    # DRBD resources which have their backing storage on one physical
    # disk sequentially. The express this use the "after" keyword.
    # after "r2";

    # 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;
  }

	#下面定义了两个节点的信息，drbd0和drbd1分别是两个节点的机器名，
# Device是drbd设备，我使用的是/dev/drbd0，这个设备是drbd自己创建的，在主节点#上，它将会使用disk /dev/hdb2这个分区上的空间，在从节点上它只记录了一些索引信#息，同步过来的数据写在disk定义的/dev/hdb2这个分区上，如果要查看同步过来的
#数据，需要先停止drbd，然后将/dev/hdb2 Mount到一个目录上就可以查看了。Address
#分别记录的是两个节点的地址和端口，端口使用默认的就行，如果drbd正常启动后两#个节点将会使用这里定义的端口进行通信，用netstat –an可以看到该端口的启动状况。

  on drbd0 {
    device     /dev/drbd0;
    disk       /dev/hdb2;
    address    10.190.40.200:7788;
    flexible-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 drbd1 {
    device    /dev/drbd0;
    disk      /dev/hdb2;
    address    10.190.40.201:7788;
    meta-disk internal;
  }
}