2009-09-26 07:07:19 +08:00
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#
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# DRBD device driver configuration
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#
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comment "DRBD disabled because PROC_FS, INET or CONNECTOR not selected"
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2009-12-29 23:38:04 +08:00
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depends on PROC_FS='n' || INET='n' || CONNECTOR='n'
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2009-09-26 07:07:19 +08:00
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config BLK_DEV_DRBD
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tristate "DRBD Distributed Replicated Block Device support"
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depends on PROC_FS && INET && CONNECTOR
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select LRU_CACHE
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default n
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help
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NOTE: In order to authenticate connections you have to select
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CRYPTO_HMAC and a hash function as well.
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DRBD is a shared-nothing, synchronously replicated block device. It
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is designed to serve as a building block for high availability
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clusters and in this context, is a "drop-in" replacement for shared
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storage. Simplistically, you could see it as a network RAID 1.
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Each minor device has a role, which can be 'primary' or 'secondary'.
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On the node with the primary device the application is supposed to
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run and to access the device (/dev/drbdX). Every write is sent to
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the local 'lower level block device' and, across the network, to the
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node with the device in 'secondary' state. The secondary device
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simply writes the data to its lower level block device.
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DRBD can also be used in dual-Primary mode (device writable on both
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nodes), which means it can exhibit shared disk semantics in a
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shared-nothing cluster. Needless to say, on top of dual-Primary
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DRBD utilizing a cluster file system is necessary to maintain for
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cache coherency.
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For automatic failover you need a cluster manager (e.g. heartbeat).
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See also: http://www.drbd.org/, http://www.linux-ha.org
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If unsure, say N.
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config DRBD_FAULT_INJECTION
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bool "DRBD fault injection"
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depends on BLK_DEV_DRBD
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help
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Say Y here if you want to simulate IO errors, in order to test DRBD's
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behavior.
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The actual simulation of IO errors is done by writing 3 values to
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/sys/module/drbd/parameters/
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enable_faults: bitmask of...
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1 meta data write
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2 read
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4 resync data write
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8 read
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16 data write
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32 data read
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64 read ahead
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128 kmalloc of bitmap
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256 allocation of EE (epoch_entries)
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fault_devs: bitmask of minor numbers
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fault_rate: frequency in percent
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Example: Simulate data write errors on /dev/drbd0 with a probability of 5%.
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echo 16 > /sys/module/drbd/parameters/enable_faults
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echo 1 > /sys/module/drbd/parameters/fault_devs
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echo 5 > /sys/module/drbd/parameters/fault_rate
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If unsure, say N.
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