The DRBD driver

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/drivers/block/drbd/Kconfig b/drivers/block/drbd/Kconfig
new file mode 100644
index 000000000000..4e6f90f487c2
--- /dev/null
+++ b/drivers/block/drbd/Kconfig
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+#
+# 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.