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authorPhilipp Reisner <philipp.reisner@linbit.com>2009-09-25 16:07:19 -0700
committerJens Axboe <jens.axboe@oracle.com>2009-10-01 21:17:49 +0200
commitb411b3637fa71fce9cf2acf0639009500f5892fe (patch)
tree6b88e5202e0f137fef50e95b0441bcafdbf91990 /Documentation/blockdev
parent1a35e0f6443f4266dad4c569c55c57a9032596fa (diff)
downloadlinux-b411b3637fa71fce9cf2acf0639009500f5892fe.tar.gz
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The DRBD driver
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'Documentation/blockdev')
-rw-r--r--Documentation/blockdev/drbd/DRBD-8.3-data-packets.svg588
-rw-r--r--Documentation/blockdev/drbd/DRBD-data-packets.svg459
-rw-r--r--Documentation/blockdev/drbd/README.txt16
-rw-r--r--Documentation/blockdev/drbd/conn-states-8.dot18
-rw-r--r--Documentation/blockdev/drbd/disk-states-8.dot16
-rw-r--r--Documentation/blockdev/drbd/drbd-connection-state-overview.dot85
-rw-r--r--Documentation/blockdev/drbd/node-states-8.dot14
7 files changed, 1196 insertions, 0 deletions
diff --git a/Documentation/blockdev/drbd/DRBD-8.3-data-packets.svg b/Documentation/blockdev/drbd/DRBD-8.3-data-packets.svg
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index 000000000000..f87cfa0dc2fb
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+++ b/Documentation/blockdev/drbd/DRBD-8.3-data-packets.svg
@@ -0,0 +1,588 @@
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+ <tspan
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diff --git a/Documentation/blockdev/drbd/DRBD-data-packets.svg b/Documentation/blockdev/drbd/DRBD-data-packets.svg
new file mode 100644
index 000000000000..48a1e2165fec
--- /dev/null
+++ b/Documentation/blockdev/drbd/DRBD-data-packets.svg
@@ -0,0 +1,459 @@
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+ width="210mm"
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+ y="7606"
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+ <tspan
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+ style="font-size:318px;font-weight:400;fill:#008000;visibility:visible;font-family:Helvetica embedded">
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+ style="font-size:318px;font-weight:400;fill:#008000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
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+ <tspan
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+ y="5202"
+ id="tspan949">al_begin_io()</tspan>
+ </text>
+ <text
+ id="text963"
+ style="font-size:318px;font-weight:400;fill:#000000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
+ x="1632 1810 1882 2060 2220 2398 2661 2839 2910 3088 3177 3355 3533 3605 3783 3888"
+ y="7331"
+ id="tspan965">al_complete_io()</tspan>
+ </text>
+ <text
+ id="text979"
+ style="font-size:318px;font-weight:400;fill:#000000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
+ x="2126 2232 2393 2571 2748 2926 3104 3176 3354 3531 3603 3781 3887"
+ y="17431"
+ id="tspan981">rs_begin_io()</tspan>
+ </text>
+ <text
+ id="text995"
+ style="font-size:318px;font-weight:400;fill:#000000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
+ x="1626 1732 1893 2071 2231 2409 2672 2849 2921 3099 3188 3366 3544 3616 3793 3899"
+ y="22331"
+ id="tspan997">rs_complete_io()</tspan>
+ </text>
+ <text
+ id="text1011"
+ style="font-size:318px;font-weight:400;fill:#000000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
+ x="16027 16133 16294 16472 16649 16827 17005 17077 17255 17432 17504 17682 17788"
+ y="18402"
+ id="tspan1013">rs_begin_io()</tspan>
+ </text>
+ <text
+ id="text1027"
+ style="font-size:318px;font-weight:400;fill:#000000;visibility:visible;font-family:Helvetica embedded">
+ <tspan
+ x="16115 16221 16382 16560 16720 16898 17161 17338 17410 17588 17677 17855 18033 18105 18282 18388"
+ y="20331"
+ id="tspan1029">rs_complete_io()</tspan>
+ </text>
+</svg>
diff --git a/Documentation/blockdev/drbd/README.txt b/Documentation/blockdev/drbd/README.txt
new file mode 100644
index 000000000000..627b0a1bf35e
--- /dev/null
+++ b/Documentation/blockdev/drbd/README.txt
@@ -0,0 +1,16 @@
+Description
+
+ DRBD is a shared-nothing, synchronously replicated block device. It
+ is designed to serve as a building block for high availability
+ clusters and in this context, is a "drop-in" replacement for shared
+ storage. Simplistically, you could see it as a network RAID 1.
+
+ Please visit http://www.drbd.org to find out more.
+
+The here included files are intended to help understand the implementation
+
+DRBD-8.3-data-packets.svg, DRBD-data-packets.svg
+ relates some functions, and write packets.
+
+conn-states-8.dot, disk-states-8.dot, node-states-8.dot
+ The sub graphs of DRBD's state transitions
diff --git a/Documentation/blockdev/drbd/conn-states-8.dot b/Documentation/blockdev/drbd/conn-states-8.dot
new file mode 100644
index 000000000000..025e8cf5e64a
--- /dev/null
+++ b/Documentation/blockdev/drbd/conn-states-8.dot
@@ -0,0 +1,18 @@
+digraph conn_states {
+ StandAllone -> WFConnection [ label = "ioctl_set_net()" ]
+ WFConnection -> Unconnected [ label = "unable to bind()" ]
+ WFConnection -> WFReportParams [ label = "in connect() after accept" ]
+ WFReportParams -> StandAllone [ label = "checks in receive_param()" ]
+ WFReportParams -> Connected [ label = "in receive_param()" ]
+ WFReportParams -> WFBitMapS [ label = "sync_handshake()" ]
+ WFReportParams -> WFBitMapT [ label = "sync_handshake()" ]
+ WFBitMapS -> SyncSource [ label = "receive_bitmap()" ]
+ WFBitMapT -> SyncTarget [ label = "receive_bitmap()" ]
+ SyncSource -> Connected
+ SyncTarget -> Connected
+ SyncSource -> PausedSyncS
+ SyncTarget -> PausedSyncT
+ PausedSyncS -> SyncSource
+ PausedSyncT -> SyncTarget
+ Connected -> WFConnection [ label = "* on network error" ]
+}
diff --git a/Documentation/blockdev/drbd/disk-states-8.dot b/Documentation/blockdev/drbd/disk-states-8.dot
new file mode 100644
index 000000000000..d06cfb46fb98
--- /dev/null
+++ b/Documentation/blockdev/drbd/disk-states-8.dot
@@ -0,0 +1,16 @@
+digraph disk_states {
+ Diskless -> Inconsistent [ label = "ioctl_set_disk()" ]
+ Diskless -> Consistent [ label = "ioctl_set_disk()" ]
+ Diskless -> Outdated [ label = "ioctl_set_disk()" ]
+ Consistent -> Outdated [ label = "receive_param()" ]
+ Consistent -> UpToDate [ label = "receive_param()" ]
+ Consistent -> Inconsistent [ label = "start resync" ]
+ Outdated -> Inconsistent [ label = "start resync" ]
+ UpToDate -> Inconsistent [ label = "ioctl_replicate" ]
+ Inconsistent -> UpToDate [ label = "resync completed" ]
+ Consistent -> Failed [ label = "io completion error" ]
+ Outdated -> Failed [ label = "io completion error" ]
+ UpToDate -> Failed [ label = "io completion error" ]
+ Inconsistent -> Failed [ label = "io completion error" ]
+ Failed -> Diskless [ label = "sending notify to peer" ]
+}
diff --git a/Documentation/blockdev/drbd/drbd-connection-state-overview.dot b/Documentation/blockdev/drbd/drbd-connection-state-overview.dot
new file mode 100644
index 000000000000..6d9cf0a7b11d
--- /dev/null
+++ b/Documentation/blockdev/drbd/drbd-connection-state-overview.dot
@@ -0,0 +1,85 @@
+// vim: set sw=2 sts=2 :
+digraph {
+ rankdir=BT
+ bgcolor=white
+
+ node [shape=plaintext]
+ node [fontcolor=black]
+
+ StandAlone [ style=filled,fillcolor=gray,label=StandAlone ]
+
+ node [fontcolor=lightgray]
+
+ Unconnected [ label=Unconnected ]
+
+ CommTrouble [ shape=record,
+ label="{communication loss|{Timeout|BrokenPipe|NetworkFailure}}" ]
+
+ node [fontcolor=gray]
+
+ subgraph cluster_try_connect {
+ label="try to connect, handshake"
+ rank=max
+ WFConnection [ label=WFConnection ]
+ WFReportParams [ label=WFReportParams ]
+ }
+
+ TearDown [ label=TearDown ]
+
+ Connected [ label=Connected,style=filled,fillcolor=green,fontcolor=black ]
+
+ node [fontcolor=lightblue]
+
+ StartingSyncS [ label=StartingSyncS ]
+ StartingSyncT [ label=StartingSyncT ]
+
+ subgraph cluster_bitmap_exchange {
+ node [fontcolor=red]
+ fontcolor=red
+ label="new application (WRITE?) requests blocked\lwhile bitmap is exchanged"
+
+ WFBitMapT [ label=WFBitMapT ]
+ WFSyncUUID [ label=WFSyncUUID ]
+ WFBitMapS [ label=WFBitMapS ]
+ }
+
+ node [fontcolor=blue]
+
+ cluster_resync [ shape=record,label="{<any>resynchronisation process running\l'concurrent' application requests allowed|{{<T>PausedSyncT\nSyncTarget}|{<S>PausedSyncS\nSyncSource}}}" ]
+
+ node [shape=box,fontcolor=black]
+
+ // drbdadm [label="drbdadm connect"]
+ // handshake [label="drbd_connect()\ndrbd_do_handshake\ndrbd_sync_handshake() etc."]
+ // comm_error [label="communication trouble"]
+
+ //
+ // edges
+ // --------------------------------------
+
+ StandAlone -> Unconnected [ label="drbdadm connect" ]
+ Unconnected -> StandAlone [ label="drbdadm disconnect\lor serious communication trouble" ]
+ Unconnected -> WFConnection [ label="receiver thread is started" ]
+ WFConnection -> WFReportParams [ headlabel="accept()\land/or \lconnect()\l" ]
+
+ WFReportParams -> StandAlone [ label="during handshake\lpeers do not agree\labout something essential" ]
+ WFReportParams -> Connected [ label="data identical\lno sync needed",color=green,fontcolor=green ]
+
+ WFReportParams -> WFBitMapS
+ WFReportParams -> WFBitMapT
+ WFBitMapT -> WFSyncUUID [minlen=0.1,constraint=false]
+
+ WFBitMapS -> cluster_resync:S
+ WFSyncUUID -> cluster_resync:T
+
+ edge [color=green]
+ cluster_resync:any -> Connected [ label="resnyc done",fontcolor=green ]
+
+ edge [color=red]
+ WFReportParams -> CommTrouble
+ Connected -> CommTrouble
+ cluster_resync:any -> CommTrouble
+ edge [color=black]
+ CommTrouble -> Unconnected [label="receiver thread is stopped" ]
+
+}
diff --git a/Documentation/blockdev/drbd/node-states-8.dot b/Documentation/blockdev/drbd/node-states-8.dot
new file mode 100644
index 000000000000..4a2b00c23547
--- /dev/null
+++ b/Documentation/blockdev/drbd/node-states-8.dot
@@ -0,0 +1,14 @@
+digraph node_states {
+ Secondary -> Primary [ label = "ioctl_set_state()" ]
+ Primary -> Secondary [ label = "ioctl_set_state()" ]
+}
+
+digraph peer_states {
+ Secondary -> Primary [ label = "recv state packet" ]
+ Primary -> Secondary [ label = "recv state packet" ]
+ Primary -> Unknown [ label = "connection lost" ]
+ Secondary -> Unknown [ label = "connection lost" ]
+ Unknown -> Primary [ label = "connected" ]
+ Unknown -> Secondary [ label = "connected" ]
+}
+