#
  # Block device driver configuration
  #

  menuconfig MD

  	bool "Multiple devices driver support (RAID and LVM)"

  	depends on BLOCK

  	help
  	  Support multiple physical spindles through a single logical device.
  	  Required for RAID and logical volume management.

  if MD

  config BLK_DEV_MD
  	tristate "RAID support"

  	---help---
  	  This driver lets you combine several hard disk partitions into one
  	  logical block device. This can be used to simply append one
  	  partition to another one or to combine several redundant hard disks
  	  into a RAID1/4/5 device so as to provide protection against hard
  	  disk failures. This is called "Software RAID" since the combining of
  	  the partitions is done by the kernel. "Hardware RAID" means that the
  	  combining is done by a dedicated controller; if you have such a
  	  controller, you do not need to say Y here.
  
  	  More information about Software RAID on Linux is contained in the
  	  Software RAID mini-HOWTO, available from
  	  <http://www.tldp.org/docs.html#howto>. There you will also learn
  	  where to get the supporting user space utilities raidtools.
  
  	  If unsure, say N.

  config MD_AUTODETECT
  	bool "Autodetect RAID arrays during kernel boot"

  	depends on BLK_DEV_MD=y

  	default y
  	---help---
  	  If you say Y here, then the kernel will try to autodetect raid
  	  arrays as part of its boot process. 
  
  	  If you don't use raid and say Y, this autodetection can cause 
  	  a several-second delay in the boot time due to various
  	  synchronisation steps that are part of this step.
  
  	  If unsure, say Y.

  config MD_LINEAR
  	tristate "Linear (append) mode"
  	depends on BLK_DEV_MD
  	---help---
  	  If you say Y here, then your multiple devices driver will be able to
  	  use the so-called linear mode, i.e. it will combine the hard disk
  	  partitions by simply appending one to the other.
  
  	  To compile this as a module, choose M here: the module
  	  will be called linear.
  
  	  If unsure, say Y.
  
  config MD_RAID0
  	tristate "RAID-0 (striping) mode"
  	depends on BLK_DEV_MD
  	---help---
  	  If you say Y here, then your multiple devices driver will be able to
  	  use the so-called raid0 mode, i.e. it will combine the hard disk
  	  partitions into one logical device in such a fashion as to fill them
  	  up evenly, one chunk here and one chunk there. This will increase
  	  the throughput rate if the partitions reside on distinct disks.
  
  	  Information about Software RAID on Linux is contained in the
  	  Software-RAID mini-HOWTO, available from
  	  <http://www.tldp.org/docs.html#howto>. There you will also
  	  learn where to get the supporting user space utilities raidtools.
  
  	  To compile this as a module, choose M here: the module
  	  will be called raid0.
  
  	  If unsure, say Y.
  
  config MD_RAID1
  	tristate "RAID-1 (mirroring) mode"
  	depends on BLK_DEV_MD
  	---help---
  	  A RAID-1 set consists of several disk drives which are exact copies
  	  of each other.  In the event of a mirror failure, the RAID driver
  	  will continue to use the operational mirrors in the set, providing
  	  an error free MD (multiple device) to the higher levels of the
  	  kernel.  In a set with N drives, the available space is the capacity
  	  of a single drive, and the set protects against a failure of (N - 1)
  	  drives.
  
  	  Information about Software RAID on Linux is contained in the
  	  Software-RAID mini-HOWTO, available from
  	  <http://www.tldp.org/docs.html#howto>.  There you will also
  	  learn where to get the supporting user space utilities raidtools.
  
  	  If you want to use such a RAID-1 set, say Y.  To compile this code
  	  as a module, choose M here: the module will be called raid1.
  
  	  If unsure, say Y.
  
  config MD_RAID10

  	tristate "RAID-10 (mirrored striping) mode"
  	depends on BLK_DEV_MD

  	---help---
  	  RAID-10 provides a combination of striping (RAID-0) and

  	  mirroring (RAID-1) with easier configuration and more flexible

  	  layout.
  	  Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
  	  be the same size (or at least, only as much as the smallest device
  	  will be used).
  	  RAID-10 provides a variety of layouts that provide different levels
  	  of redundancy and performance.
  
  	  RAID-10 requires mdadm-1.7.0 or later, available at:
  
  	  ftp://ftp.kernel.org/pub/linux/utils/raid/mdadm/
  
  	  If unsure, say Y.

  config MD_RAID456
  	tristate "RAID-4/RAID-5/RAID-6 mode"

  	depends on BLK_DEV_MD

  	select RAID6_PQ

  	select ASYNC_MEMCPY
  	select ASYNC_XOR

  	select ASYNC_PQ
  	select ASYNC_RAID6_RECOV

  	---help---
  	  A RAID-5 set of N drives with a capacity of C MB per drive provides
  	  the capacity of C * (N - 1) MB, and protects against a failure
  	  of a single drive. For a given sector (row) number, (N - 1) drives
  	  contain data sectors, and one drive contains the parity protection.
  	  For a RAID-4 set, the parity blocks are present on a single drive,
  	  while a RAID-5 set distributes the parity across the drives in one
  	  of the available parity distribution methods.

  	  A RAID-6 set of N drives with a capacity of C MB per drive
  	  provides the capacity of C * (N - 2) MB, and protects
  	  against a failure of any two drives. For a given sector
  	  (row) number, (N - 2) drives contain data sectors, and two
  	  drives contains two independent redundancy syndromes.  Like
  	  RAID-5, RAID-6 distributes the syndromes across the drives
  	  in one of the available parity distribution methods.

  	  Information about Software RAID on Linux is contained in the
  	  Software-RAID mini-HOWTO, available from
  	  <http://www.tldp.org/docs.html#howto>. There you will also
  	  learn where to get the supporting user space utilities raidtools.

  	  If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y.  To

  	  compile this code as a module, choose M here: the module

  	  will be called raid456.

  
  	  If unsure, say Y.

  config MULTICORE_RAID456
  	bool "RAID-4/RAID-5/RAID-6 Multicore processing (EXPERIMENTAL)"
  	depends on MD_RAID456
  	depends on SMP
  	depends on EXPERIMENTAL
  	---help---
  	  Enable the raid456 module to dispatch per-stripe raid operations to a
  	  thread pool.
  
  	  If unsure, say N.

  config MD_MULTIPATH
  	tristate "Multipath I/O support"
  	depends on BLK_DEV_MD
  	help

  	  MD_MULTIPATH provides a simple multi-path personality for use
  	  the MD framework.  It is not under active development.  New
  	  projects should consider using DM_MULTIPATH which has more
  	  features and more testing.

  
  	  If unsure, say N.
  
  config MD_FAULTY
  	tristate "Faulty test module for MD"
  	depends on BLK_DEV_MD
  	help
  	  The "faulty" module allows for a block device that occasionally returns
  	  read or write errors.  It is useful for testing.
  
  	  In unsure, say N.
  
  config BLK_DEV_DM
  	tristate "Device mapper support"

  	---help---
  	  Device-mapper is a low level volume manager.  It works by allowing
  	  people to specify mappings for ranges of logical sectors.  Various
  	  mapping types are available, in addition people may write their own
  	  modules containing custom mappings if they wish.
  
  	  Higher level volume managers such as LVM2 use this driver.
  
  	  To compile this as a module, choose M here: the module will be
  	  called dm-mod.
  
  	  If unsure, say N.

  config DM_DEBUG
  	boolean "Device mapper debugging support"

  	depends on BLK_DEV_DM

  	---help---
  	  Enable this for messages that may help debug device-mapper problems.
  
  	  If unsure, say N.

  config DM_BUFIO
         tristate
         depends on BLK_DEV_DM && EXPERIMENTAL
         ---help---
  	 This interface allows you to do buffered I/O on a device and acts
  	 as a cache, holding recently-read blocks in memory and performing
  	 delayed writes.

  source "drivers/md/persistent-data/Kconfig"

  config DM_CRYPT
  	tristate "Crypt target support"

  	depends on BLK_DEV_DM

  	select CRYPTO

  	select CRYPTO_CBC

  	---help---
  	  This device-mapper target allows you to create a device that
  	  transparently encrypts the data on it. You'll need to activate
  	  the ciphers you're going to use in the cryptoapi configuration.
  
  	  Information on how to use dm-crypt can be found on
  
  	  <http://www.saout.de/misc/dm-crypt/>
  
  	  To compile this code as a module, choose M here: the module will
  	  be called dm-crypt.
  
  	  If unsure, say N.
  
  config DM_SNAPSHOT

         tristate "Snapshot target"
         depends on BLK_DEV_DM

         ---help---

           Allow volume managers to take writable snapshots of a device.

  config DM_THIN_PROVISIONING
         tristate "Thin provisioning target (EXPERIMENTAL)"
         depends on BLK_DEV_DM && EXPERIMENTAL
         select DM_PERSISTENT_DATA
         ---help---
           Provides thin provisioning and snapshots that share a data store.
  
  config DM_DEBUG_BLOCK_STACK_TRACING
  	boolean "Keep stack trace of thin provisioning block lock holders"
  	depends on STACKTRACE_SUPPORT && DM_THIN_PROVISIONING
  	select STACKTRACE
  	---help---
  	  Enable this for messages that may help debug problems with the
  	  block manager locking used by thin provisioning.
  
  	  If unsure, say N.
  
  config DM_DEBUG_SPACE_MAPS
  	boolean "Extra validation for thin provisioning space maps"
  	depends on DM_THIN_PROVISIONING
  	---help---
  	  Enable this for messages that may help debug problems with the
  	  space maps used by thin provisioning.
  
            If unsure, say N.

  config DM_MIRROR

         tristate "Mirror target"
         depends on BLK_DEV_DM

         ---help---
           Allow volume managers to mirror logical volumes, also
           needed for live data migration tools such as 'pvmove'.

  config DM_RAID

         tristate "RAID 1/4/5/6 target (EXPERIMENTAL)"

         depends on BLK_DEV_DM && EXPERIMENTAL

         select MD_RAID1

         select MD_RAID456
         select BLK_DEV_MD
         ---help---

  	 A dm target that supports RAID1, RAID4, RAID5 and RAID6 mappings

  
  	 A RAID-5 set of N drives with a capacity of C MB per drive provides
  	 the capacity of C * (N - 1) MB, and protects against a failure
  	 of a single drive. For a given sector (row) number, (N - 1) drives
  	 contain data sectors, and one drive contains the parity protection.
  	 For a RAID-4 set, the parity blocks are present on a single drive,
  	 while a RAID-5 set distributes the parity across the drives in one
  	 of the available parity distribution methods.
  
  	 A RAID-6 set of N drives with a capacity of C MB per drive
  	 provides the capacity of C * (N - 2) MB, and protects
  	 against a failure of any two drives. For a given sector
  	 (row) number, (N - 2) drives contain data sectors, and two
  	 drives contains two independent redundancy syndromes.  Like
  	 RAID-5, RAID-6 distributes the syndromes across the drives
  	 in one of the available parity distribution methods.

  config DM_LOG_USERSPACE
  	tristate "Mirror userspace logging (EXPERIMENTAL)"
  	depends on DM_MIRROR && EXPERIMENTAL && NET
  	select CONNECTOR
  	---help---
  	  The userspace logging module provides a mechanism for
  	  relaying the dm-dirty-log API to userspace.  Log designs
  	  which are more suited to userspace implementation (e.g.
  	  shared storage logs) or experimental logs can be implemented
  	  by leveraging this framework.

  config DM_ZERO

  	tristate "Zero target"
  	depends on BLK_DEV_DM

  	---help---
  	  A target that discards writes, and returns all zeroes for
  	  reads.  Useful in some recovery situations.
  
  config DM_MULTIPATH

  	tristate "Multipath target"
  	depends on BLK_DEV_DM

  	# nasty syntax but means make DM_MULTIPATH independent
  	# of SCSI_DH if the latter isn't defined but if
  	# it is, DM_MULTIPATH must depend on it.  We get a build
  	# error if SCSI_DH=m and DM_MULTIPATH=y
  	depends on SCSI_DH || !SCSI_DH

  	---help---
  	  Allow volume managers to support multipath hardware.

  config DM_MULTIPATH_QL
  	tristate "I/O Path Selector based on the number of in-flight I/Os"
  	depends on DM_MULTIPATH
  	---help---
  	  This path selector is a dynamic load balancer which selects
  	  the path with the least number of in-flight I/Os.
  
  	  If unsure, say N.

  config DM_MULTIPATH_ST
  	tristate "I/O Path Selector based on the service time"
  	depends on DM_MULTIPATH
  	---help---
  	  This path selector is a dynamic load balancer which selects
  	  the path expected to complete the incoming I/O in the shortest
  	  time.
  
  	  If unsure, say N.

  config DM_DELAY
  	tristate "I/O delaying target (EXPERIMENTAL)"
  	depends on BLK_DEV_DM && EXPERIMENTAL
  	---help---
  	A target that delays reads and/or writes and can send
  	them to different devices.  Useful for testing.
  
  	If unsure, say N.

  config DM_UEVENT
  	bool "DM uevents (EXPERIMENTAL)"
  	depends on BLK_DEV_DM && EXPERIMENTAL
  	---help---
  	Generate udev events for DM events.

  config DM_FLAKEY
         tristate "Flakey target (EXPERIMENTAL)"
         depends on BLK_DEV_DM && EXPERIMENTAL
         ---help---
           A target that intermittently fails I/O for debugging purposes.

  endif # MD