The DRBD driver
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/Kconfig b/drivers/block/drbd/Kconfig
new file mode 100644
index 0000000..4e6f90f
--- /dev/null
+++ b/drivers/block/drbd/Kconfig
@@ -0,0 +1,82 @@
+#
+# DRBD device driver configuration
+#
+
+comment "DRBD disabled because PROC_FS, INET or CONNECTOR not selected"
+ depends on !PROC_FS || !INET || !CONNECTOR
+
+config BLK_DEV_DRBD
+ tristate "DRBD Distributed Replicated Block Device support"
+ depends on PROC_FS && INET && CONNECTOR
+ select LRU_CACHE
+ default n
+ help
+
+ NOTE: In order to authenticate connections you have to select
+ CRYPTO_HMAC and a hash function as well.
+
+ 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.
+
+ Each minor device has a role, which can be 'primary' or 'secondary'.
+ On the node with the primary device the application is supposed to
+ run and to access the device (/dev/drbdX). Every write is sent to
+ the local 'lower level block device' and, across the network, to the
+ node with the device in 'secondary' state. The secondary device
+ simply writes the data to its lower level block device.
+
+ DRBD can also be used in dual-Primary mode (device writable on both
+ nodes), which means it can exhibit shared disk semantics in a
+ shared-nothing cluster. Needless to say, on top of dual-Primary
+ DRBD utilizing a cluster file system is necessary to maintain for
+ cache coherency.
+
+ For automatic failover you need a cluster manager (e.g. heartbeat).
+ See also: http://www.drbd.org/, http://www.linux-ha.org
+
+ If unsure, say N.
+
+config DRBD_TRACE
+ tristate "DRBD tracing"
+ depends on BLK_DEV_DRBD
+ select TRACEPOINTS
+ default n
+ help
+
+ Say Y here if you want to be able to trace various events in DRBD.
+
+ If unsure, say N.
+
+config DRBD_FAULT_INJECTION
+ bool "DRBD fault injection"
+ depends on BLK_DEV_DRBD
+ help
+
+ Say Y here if you want to simulate IO errors, in order to test DRBD's
+ behavior.
+
+ The actual simulation of IO errors is done by writing 3 values to
+ /sys/module/drbd/parameters/
+
+ enable_faults: bitmask of...
+ 1 meta data write
+ 2 read
+ 4 resync data write
+ 8 read
+ 16 data write
+ 32 data read
+ 64 read ahead
+ 128 kmalloc of bitmap
+ 256 allocation of EE (epoch_entries)
+
+ fault_devs: bitmask of minor numbers
+ fault_rate: frequency in percent
+
+ Example: Simulate data write errors on /dev/drbd0 with a probability of 5%.
+ echo 16 > /sys/module/drbd/parameters/enable_faults
+ echo 1 > /sys/module/drbd/parameters/fault_devs
+ echo 5 > /sys/module/drbd/parameters/fault_rate
+
+ If unsure, say N.