LXR linux/drivers/block/drbd/Kconfig

   1#
   2# DRBD device driver configuration
   3#
   4
   5comment "DRBD disabled because PROC_FS or INET not selected"
   6        depends on PROC_FS='n' || INET='n'
   7
   8config BLK_DEV_DRBD
   9        tristate "DRBD Distributed Replicated Block Device support"
  10        depends on PROC_FS && INET
  11        select LRU_CACHE
  12        select LIBCRC32C
  13        default n
  14        help
  15
  16          NOTE: In order to authenticate connections you have to select
  17          CRYPTO_HMAC and a hash function as well.
  18
  19          DRBD is a shared-nothing, synchronously replicated block device. It
  20          is designed to serve as a building block for high availability
  21          clusters and in this context, is a "drop-in" replacement for shared
  22          storage. Simplistically, you could see it as a network RAID 1.
  23
  24          Each minor device has a role, which can be 'primary' or 'secondary'.
  25          On the node with the primary device the application is supposed to
  26          run and to access the device (/dev/drbdX). Every write is sent to
  27          the local 'lower level block device' and, across the network, to the
  28          node with the device in 'secondary' state.  The secondary device
  29          simply writes the data to its lower level block device.
  30
  31          DRBD can also be used in dual-Primary mode (device writable on both
  32          nodes), which means it can exhibit shared disk semantics in a
  33          shared-nothing cluster.  Needless to say, on top of dual-Primary
  34          DRBD utilizing a cluster file system is necessary to maintain for
  35          cache coherency.
  36
  37          For automatic failover you need a cluster manager (e.g. heartbeat).
  38          See also: http://www.drbd.org/, http://www.linux-ha.org
  39
  40          If unsure, say N.
  41
  42config DRBD_FAULT_INJECTION
  43        bool "DRBD fault injection"
  44        depends on BLK_DEV_DRBD
  45        help
  46
  47          Say Y here if you want to simulate IO errors, in order to test DRBD's
  48          behavior.
  49
  50          The actual simulation of IO errors is done by writing 3 values to
  51          /sys/module/drbd/parameters/
  52
  53          enable_faults: bitmask of...
  54          1     meta data write
  55          2               read
  56          4     resync data write
  57          8                 read
  58          16    data write
  59          32    data read
  60          64    read ahead
  61          128   kmalloc of bitmap
  62          256   allocation of peer_requests
  63          512   insert data corruption on receiving side
  64
  65          fault_devs: bitmask of minor numbers
  66          fault_rate: frequency in percent
  67
  68          Example: Simulate data write errors on /dev/drbd0 with a probability of 5%.
  69                echo 16 > /sys/module/drbd/parameters/enable_faults
  70                echo 1 > /sys/module/drbd/parameters/fault_devs
  71                echo 5 > /sys/module/drbd/parameters/fault_rate
  72
  73          If unsure, say N.
  74