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kernel/linux-rt-4.4.41/drivers/block/drbd/Kconfig 2.38 KB
5113f6f70   김현기   kernel add
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  #
  # DRBD device driver configuration
  #
  
  comment "DRBD disabled because PROC_FS or INET not selected"
  	depends on PROC_FS='n' || INET='n'
  
  config BLK_DEV_DRBD
  	tristate "DRBD Distributed Replicated Block Device support"
  	depends on PROC_FS && INET
  	select LRU_CACHE
  	select LIBCRC32C
  	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_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 peer_requests
  	  512	insert data corruption on receiving side
  
  	  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.