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The conversion is actually: - add blank lines and indentation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Mark Brown <broonie@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
574 lines
18 KiB
Plaintext
574 lines
18 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0-only
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#
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# Block device driver configuration
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#
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menuconfig MD
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bool "Multiple devices driver support (RAID and LVM)"
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depends on BLOCK
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select SRCU
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help
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Support multiple physical spindles through a single logical device.
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Required for RAID and logical volume management.
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if MD
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config BLK_DEV_MD
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tristate "RAID support"
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---help---
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This driver lets you combine several hard disk partitions into one
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logical block device. This can be used to simply append one
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partition to another one or to combine several redundant hard disks
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into a RAID1/4/5 device so as to provide protection against hard
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disk failures. This is called "Software RAID" since the combining of
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the partitions is done by the kernel. "Hardware RAID" means that the
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combining is done by a dedicated controller; if you have such a
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controller, you do not need to say Y here.
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More information about Software RAID on Linux is contained in the
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Software RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also learn
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where to get the supporting user space utilities raidtools.
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If unsure, say N.
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config MD_AUTODETECT
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bool "Autodetect RAID arrays during kernel boot"
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depends on BLK_DEV_MD=y
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default y
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---help---
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If you say Y here, then the kernel will try to autodetect raid
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arrays as part of its boot process.
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If you don't use raid and say Y, this autodetection can cause
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a several-second delay in the boot time due to various
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synchronisation steps that are part of this step.
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If unsure, say Y.
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config MD_LINEAR
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tristate "Linear (append) mode"
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depends on BLK_DEV_MD
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---help---
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If you say Y here, then your multiple devices driver will be able to
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use the so-called linear mode, i.e. it will combine the hard disk
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partitions by simply appending one to the other.
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To compile this as a module, choose M here: the module
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will be called linear.
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If unsure, say Y.
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config MD_RAID0
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tristate "RAID-0 (striping) mode"
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depends on BLK_DEV_MD
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---help---
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If you say Y here, then your multiple devices driver will be able to
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use the so-called raid0 mode, i.e. it will combine the hard disk
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partitions into one logical device in such a fashion as to fill them
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up evenly, one chunk here and one chunk there. This will increase
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the throughput rate if the partitions reside on distinct disks.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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To compile this as a module, choose M here: the module
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will be called raid0.
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If unsure, say Y.
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config MD_RAID1
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tristate "RAID-1 (mirroring) mode"
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depends on BLK_DEV_MD
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---help---
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A RAID-1 set consists of several disk drives which are exact copies
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of each other. In the event of a mirror failure, the RAID driver
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will continue to use the operational mirrors in the set, providing
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an error free MD (multiple device) to the higher levels of the
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kernel. In a set with N drives, the available space is the capacity
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of a single drive, and the set protects against a failure of (N - 1)
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drives.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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If you want to use such a RAID-1 set, say Y. To compile this code
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as a module, choose M here: the module will be called raid1.
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If unsure, say Y.
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config MD_RAID10
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tristate "RAID-10 (mirrored striping) mode"
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depends on BLK_DEV_MD
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---help---
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RAID-10 provides a combination of striping (RAID-0) and
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mirroring (RAID-1) with easier configuration and more flexible
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layout.
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Unlike RAID-0, but like RAID-1, RAID-10 requires all devices to
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be the same size (or at least, only as much as the smallest device
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will be used).
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RAID-10 provides a variety of layouts that provide different levels
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of redundancy and performance.
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RAID-10 requires mdadm-1.7.0 or later, available at:
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https://www.kernel.org/pub/linux/utils/raid/mdadm/
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If unsure, say Y.
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config MD_RAID456
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tristate "RAID-4/RAID-5/RAID-6 mode"
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depends on BLK_DEV_MD
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select RAID6_PQ
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select LIBCRC32C
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select ASYNC_MEMCPY
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select ASYNC_XOR
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select ASYNC_PQ
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select ASYNC_RAID6_RECOV
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---help---
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A RAID-5 set of N drives with a capacity of C MB per drive provides
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the capacity of C * (N - 1) MB, and protects against a failure
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of a single drive. For a given sector (row) number, (N - 1) drives
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contain data sectors, and one drive contains the parity protection.
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For a RAID-4 set, the parity blocks are present on a single drive,
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while a RAID-5 set distributes the parity across the drives in one
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of the available parity distribution methods.
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A RAID-6 set of N drives with a capacity of C MB per drive
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provides the capacity of C * (N - 2) MB, and protects
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against a failure of any two drives. For a given sector
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(row) number, (N - 2) drives contain data sectors, and two
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drives contains two independent redundancy syndromes. Like
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RAID-5, RAID-6 distributes the syndromes across the drives
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in one of the available parity distribution methods.
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Information about Software RAID on Linux is contained in the
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Software-RAID mini-HOWTO, available from
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<http://www.tldp.org/docs.html#howto>. There you will also
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learn where to get the supporting user space utilities raidtools.
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If you want to use such a RAID-4/RAID-5/RAID-6 set, say Y. To
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compile this code as a module, choose M here: the module
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will be called raid456.
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If unsure, say Y.
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config MD_MULTIPATH
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tristate "Multipath I/O support"
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depends on BLK_DEV_MD
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help
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MD_MULTIPATH provides a simple multi-path personality for use
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the MD framework. It is not under active development. New
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projects should consider using DM_MULTIPATH which has more
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features and more testing.
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If unsure, say N.
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config MD_FAULTY
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tristate "Faulty test module for MD"
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depends on BLK_DEV_MD
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help
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The "faulty" module allows for a block device that occasionally returns
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read or write errors. It is useful for testing.
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In unsure, say N.
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config MD_CLUSTER
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tristate "Cluster Support for MD"
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depends on BLK_DEV_MD
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depends on DLM
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default n
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---help---
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Clustering support for MD devices. This enables locking and
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synchronization across multiple systems on the cluster, so all
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nodes in the cluster can access the MD devices simultaneously.
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This brings the redundancy (and uptime) of RAID levels across the
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nodes of the cluster. Currently, it can work with raid1 and raid10
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(limited support).
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If unsure, say N.
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source "drivers/md/bcache/Kconfig"
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config BLK_DEV_DM_BUILTIN
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bool
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config BLK_DEV_DM
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tristate "Device mapper support"
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select BLK_DEV_DM_BUILTIN
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depends on DAX || DAX=n
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---help---
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Device-mapper is a low level volume manager. It works by allowing
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people to specify mappings for ranges of logical sectors. Various
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mapping types are available, in addition people may write their own
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modules containing custom mappings if they wish.
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Higher level volume managers such as LVM2 use this driver.
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To compile this as a module, choose M here: the module will be
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called dm-mod.
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If unsure, say N.
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config DM_DEBUG
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bool "Device mapper debugging support"
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depends on BLK_DEV_DM
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---help---
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Enable this for messages that may help debug device-mapper problems.
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If unsure, say N.
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config DM_BUFIO
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tristate
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depends on BLK_DEV_DM
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---help---
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This interface allows you to do buffered I/O on a device and acts
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as a cache, holding recently-read blocks in memory and performing
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delayed writes.
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config DM_DEBUG_BLOCK_MANAGER_LOCKING
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bool "Block manager locking"
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depends on DM_BUFIO
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---help---
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Block manager locking can catch various metadata corruption issues.
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If unsure, say N.
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config DM_DEBUG_BLOCK_STACK_TRACING
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bool "Keep stack trace of persistent data block lock holders"
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depends on STACKTRACE_SUPPORT && DM_DEBUG_BLOCK_MANAGER_LOCKING
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select STACKTRACE
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---help---
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Enable this for messages that may help debug problems with the
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block manager locking used by thin provisioning and caching.
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If unsure, say N.
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config DM_BIO_PRISON
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tristate
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depends on BLK_DEV_DM
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---help---
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Some bio locking schemes used by other device-mapper targets
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including thin provisioning.
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source "drivers/md/persistent-data/Kconfig"
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config DM_UNSTRIPED
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tristate "Unstriped target"
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depends on BLK_DEV_DM
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---help---
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Unstripes I/O so it is issued solely on a single drive in a HW
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RAID0 or dm-striped target.
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config DM_CRYPT
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tristate "Crypt target support"
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depends on BLK_DEV_DM
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select CRYPTO
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select CRYPTO_CBC
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---help---
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This device-mapper target allows you to create a device that
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transparently encrypts the data on it. You'll need to activate
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the ciphers you're going to use in the cryptoapi configuration.
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For further information on dm-crypt and userspace tools see:
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<https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt>
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To compile this code as a module, choose M here: the module will
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be called dm-crypt.
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If unsure, say N.
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config DM_SNAPSHOT
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tristate "Snapshot target"
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depends on BLK_DEV_DM
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select DM_BUFIO
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---help---
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Allow volume managers to take writable snapshots of a device.
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config DM_THIN_PROVISIONING
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tristate "Thin provisioning target"
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depends on BLK_DEV_DM
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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Provides thin provisioning and snapshots that share a data store.
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config DM_CACHE
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tristate "Cache target (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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default n
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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dm-cache attempts to improve performance of a block device by
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moving frequently used data to a smaller, higher performance
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device. Different 'policy' plugins can be used to change the
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algorithms used to select which blocks are promoted, demoted,
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cleaned etc. It supports writeback and writethrough modes.
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config DM_CACHE_SMQ
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tristate "Stochastic MQ Cache Policy (EXPERIMENTAL)"
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depends on DM_CACHE
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default y
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---help---
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A cache policy that uses a multiqueue ordered by recent hits
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to select which blocks should be promoted and demoted.
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This is meant to be a general purpose policy. It prioritises
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reads over writes. This SMQ policy (vs MQ) offers the promise
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of less memory utilization, improved performance and increased
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adaptability in the face of changing workloads.
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config DM_WRITECACHE
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tristate "Writecache target"
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depends on BLK_DEV_DM
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---help---
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The writecache target caches writes on persistent memory or SSD.
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It is intended for databases or other programs that need extremely
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low commit latency.
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The writecache target doesn't cache reads because reads are supposed
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to be cached in standard RAM.
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config DM_ERA
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tristate "Era target (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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default n
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select DM_PERSISTENT_DATA
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select DM_BIO_PRISON
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---help---
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dm-era tracks which parts of a block device are written to
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over time. Useful for maintaining cache coherency when using
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vendor snapshots.
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config DM_MIRROR
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tristate "Mirror target"
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depends on BLK_DEV_DM
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---help---
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Allow volume managers to mirror logical volumes, also
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needed for live data migration tools such as 'pvmove'.
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config DM_LOG_USERSPACE
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tristate "Mirror userspace logging"
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depends on DM_MIRROR && NET
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select CONNECTOR
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---help---
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The userspace logging module provides a mechanism for
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relaying the dm-dirty-log API to userspace. Log designs
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which are more suited to userspace implementation (e.g.
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shared storage logs) or experimental logs can be implemented
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by leveraging this framework.
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config DM_RAID
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tristate "RAID 1/4/5/6/10 target"
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depends on BLK_DEV_DM
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select MD_RAID0
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select MD_RAID1
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select MD_RAID10
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select MD_RAID456
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select BLK_DEV_MD
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---help---
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A dm target that supports RAID1, RAID10, RAID4, RAID5 and RAID6 mappings
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A RAID-5 set of N drives with a capacity of C MB per drive provides
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the capacity of C * (N - 1) MB, and protects against a failure
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of a single drive. For a given sector (row) number, (N - 1) drives
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contain data sectors, and one drive contains the parity protection.
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For a RAID-4 set, the parity blocks are present on a single drive,
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while a RAID-5 set distributes the parity across the drives in one
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of the available parity distribution methods.
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A RAID-6 set of N drives with a capacity of C MB per drive
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provides the capacity of C * (N - 2) MB, and protects
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against a failure of any two drives. For a given sector
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(row) number, (N - 2) drives contain data sectors, and two
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drives contains two independent redundancy syndromes. Like
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RAID-5, RAID-6 distributes the syndromes across the drives
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in one of the available parity distribution methods.
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config DM_ZERO
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tristate "Zero target"
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depends on BLK_DEV_DM
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---help---
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A target that discards writes, and returns all zeroes for
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reads. Useful in some recovery situations.
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config DM_MULTIPATH
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tristate "Multipath target"
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depends on BLK_DEV_DM
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# nasty syntax but means make DM_MULTIPATH independent
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# of SCSI_DH if the latter isn't defined but if
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# it is, DM_MULTIPATH must depend on it. We get a build
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# error if SCSI_DH=m and DM_MULTIPATH=y
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depends on !SCSI_DH || SCSI
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---help---
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Allow volume managers to support multipath hardware.
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config DM_MULTIPATH_QL
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tristate "I/O Path Selector based on the number of in-flight I/Os"
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depends on DM_MULTIPATH
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---help---
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This path selector is a dynamic load balancer which selects
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the path with the least number of in-flight I/Os.
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If unsure, say N.
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config DM_MULTIPATH_ST
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tristate "I/O Path Selector based on the service time"
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depends on DM_MULTIPATH
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---help---
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This path selector is a dynamic load balancer which selects
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the path expected to complete the incoming I/O in the shortest
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time.
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If unsure, say N.
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config DM_DELAY
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tristate "I/O delaying target"
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depends on BLK_DEV_DM
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---help---
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A target that delays reads and/or writes and can send
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them to different devices. Useful for testing.
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If unsure, say N.
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config DM_DUST
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tristate "Bad sector simulation target"
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depends on BLK_DEV_DM
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---help---
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A target that simulates bad sector behavior.
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Useful for testing.
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If unsure, say N.
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config DM_INIT
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bool "DM \"dm-mod.create=\" parameter support"
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depends on BLK_DEV_DM=y
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---help---
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Enable "dm-mod.create=" parameter to create mapped devices at init time.
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This option is useful to allow mounting rootfs without requiring an
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initramfs.
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See Documentation/device-mapper/dm-init.rst for dm-mod.create="..."
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format.
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If unsure, say N.
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config DM_UEVENT
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bool "DM uevents"
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depends on BLK_DEV_DM
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---help---
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Generate udev events for DM events.
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config DM_FLAKEY
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tristate "Flakey target"
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depends on BLK_DEV_DM
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---help---
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A target that intermittently fails I/O for debugging purposes.
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config DM_VERITY
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tristate "Verity target support"
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depends on BLK_DEV_DM
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select CRYPTO
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select CRYPTO_HASH
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select DM_BUFIO
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---help---
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This device-mapper target creates a read-only device that
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transparently validates the data on one underlying device against
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a pre-generated tree of cryptographic checksums stored on a second
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device.
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You'll need to activate the digests you're going to use in the
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cryptoapi configuration.
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To compile this code as a module, choose M here: the module will
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be called dm-verity.
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If unsure, say N.
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config DM_VERITY_FEC
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bool "Verity forward error correction support"
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depends on DM_VERITY
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select REED_SOLOMON
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select REED_SOLOMON_DEC8
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---help---
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Add forward error correction support to dm-verity. This option
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makes it possible to use pre-generated error correction data to
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recover from corrupted blocks.
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If unsure, say N.
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config DM_SWITCH
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tristate "Switch target support (EXPERIMENTAL)"
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depends on BLK_DEV_DM
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---help---
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This device-mapper target creates a device that supports an arbitrary
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mapping of fixed-size regions of I/O across a fixed set of paths.
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The path used for any specific region can be switched dynamically
|
|
by sending the target a message.
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called dm-switch.
|
|
|
|
If unsure, say N.
|
|
|
|
config DM_LOG_WRITES
|
|
tristate "Log writes target support"
|
|
depends on BLK_DEV_DM
|
|
---help---
|
|
This device-mapper target takes two devices, one device to use
|
|
normally, one to log all write operations done to the first device.
|
|
This is for use by file system developers wishing to verify that
|
|
their fs is writing a consistent file system at all times by allowing
|
|
them to replay the log in a variety of ways and to check the
|
|
contents.
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called dm-log-writes.
|
|
|
|
If unsure, say N.
|
|
|
|
config DM_INTEGRITY
|
|
tristate "Integrity target support"
|
|
depends on BLK_DEV_DM
|
|
select BLK_DEV_INTEGRITY
|
|
select DM_BUFIO
|
|
select CRYPTO
|
|
select ASYNC_XOR
|
|
---help---
|
|
This device-mapper target emulates a block device that has
|
|
additional per-sector tags that can be used for storing
|
|
integrity information.
|
|
|
|
This integrity target is used with the dm-crypt target to
|
|
provide authenticated disk encryption or it can be used
|
|
standalone.
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called dm-integrity.
|
|
|
|
config DM_ZONED
|
|
tristate "Drive-managed zoned block device target support"
|
|
depends on BLK_DEV_DM
|
|
depends on BLK_DEV_ZONED
|
|
---help---
|
|
This device-mapper target takes a host-managed or host-aware zoned
|
|
block device and exposes most of its capacity as a regular block
|
|
device (drive-managed zoned block device) without any write
|
|
constraints. This is mainly intended for use with file systems that
|
|
do not natively support zoned block devices but still want to
|
|
benefit from the increased capacity offered by SMR disks. Other uses
|
|
by applications using raw block devices (for example object stores)
|
|
are also possible.
|
|
|
|
To compile this code as a module, choose M here: the module will
|
|
be called dm-zoned.
|
|
|
|
If unsure, say N.
|
|
|
|
endif # MD
|