imsm: Correct minimal device size.

[thirdparty/mdadm.git] / mdadm.conf.5

diff --git a/mdadm.conf.5 b/mdadm.conf.5
index aadfb23e3f0f515ba57b02c9a976386763115eca..27dbab18455d145790e502e101b1a02947ef7d13 100644 (file)
--- a/mdadm.conf.5
+++ b/mdadm.conf.5
@@ -11,7 +11,7 @@ mdadm.conf \- configuration for management of Software RAID with mdadm
 /etc/mdadm.conf
 .SH DESCRIPTION
 .PP
 /etc/mdadm.conf
 .SH DESCRIPTION
 .PP

-.B mdadm
+.I mdadm

 is a tool for creating, managing, and monitoring RAID devices using the
 .B md
 driver in Linux.
 is a tool for creating, managing, and monitoring RAID devices using the
 .B md
 driver in Linux.


@@ -25,6 +25,16 @@ space (space, tab, or newline).
 Any word that beings with a hash sign (#) starts a comment and that
 word together with the remainder of the line is ignored.
 
 Any word that beings with a hash sign (#) starts a comment and that
 word together with the remainder of the line is ignored.
 

+Spaces can be included in a word using quotation characters.  Either
+single quotes
+.RB ( ' )
+or double quotes (\fB"\fP)
+may be used.  All the characters from one quotation character to
+next identical character are protected and will not be used to
+separate words to start new quoted strings.  To include a single quote
+it must be between double quotes.  To include a double quote it must
+be between single quotes.
+

 Any line that starts with white space (space or tab) is treated as
 though it were a continuation of the previous line.
 
 Any line that starts with white space (space or tab) is treated as
 though it were a continuation of the previous line.
 


@@ -40,7 +50,7 @@ A
 line lists the devices (whole devices or partitions) that might contain
 a component of an MD array.  When looking for the components of an
 array,
 line lists the devices (whole devices or partitions) that might contain
 a component of an MD array.  When looking for the components of an
 array,

-.B mdadm
+.I mdadm

 will scan these devices (or any devices listed on the command line).
 
 The
 will scan these devices (or any devices listed on the command line).
 
 The


@@ -53,9 +63,20 @@ Also, there may be several device lines present in the file.
 
 Alternatively, a
 .B device
 
 Alternatively, a
 .B device

-line can contain the word
+line can contain either or both of the  words
+.B containers
+and

 .BR partitions .
 .BR partitions .

-This will cause
+The word
+.B containers
+will cause
+.I mdadm
+to look for assembled CONTAINER arrays and included them as a source
+for assembling further arrays.
+
+The word
+.I partitions
+will cause

 .I mdadm
 to read
 .I /proc/partitions
 .I mdadm
 to read
 .I /proc/partitions


@@ -67,7 +88,7 @@ but only the major and minor device numbers.  It scans
 .I /dev
 to find the name that matches the numbers.
 
 .I /dev
 to find the name that matches the numbers.
 

-If no DEVICE line is present, then "DEVICE partitions" is assumed.
+If no DEVICE line is present, then "DEVICE partitions containers" is assumed.

 
 For example:
 .IP
 
 For example:
 .IP


@@ -75,22 +96,35 @@ DEVICE /dev/hda* /dev/hdc*
 .br
 DEV    /dev/sd*
 .br
 .br
 DEV    /dev/sd*
 .br

-DEVICE /dev/discs/disc*/disc
+DEVICE /dev/disk/by-path/pci*

 .br
 DEVICE partitions
 
 .TP
 .B ARRAY
 The ARRAY lines identify actual arrays.  The second word on the line
 .br
 DEVICE partitions
 
 .TP
 .B ARRAY
 The ARRAY lines identify actual arrays.  The second word on the line

-should be the name of the device where the array is normally
+may be the name of the device where the array is normally

 assembled, such as
 assembled, such as

-.BR  /dev/md1 .
+.B /dev/md1
+or
+.BR /dev/md/backup .
+If the name does not start with a slash
+.RB (' / '),
+it is treated as being in
+.BR /dev/md/ .
+Alternately the word
+.B <ignore>
+(complete with angle brackets) can be given in which case any array
+which matches the rest of the line will never be automatically assembled.
+If no device name is given,
+.I mdadm
+will use various heuristics to determine an appropriate name.
+

 Subsequent words identify the array, or identify the array as a member
 of a group. If multiple identities are given,
 then a component device must match ALL identities to be considered a
 match.  Each identity word has a tag, and equals sign, and some value.
 The tags are:
 Subsequent words identify the array, or identify the array as a member
 of a group. If multiple identities are given,
 then a component device must match ALL identities to be considered a
 match.  Each identity word has a tag, and equals sign, and some value.
 The tags are:

-

 .RS 4
 .TP
 .B uuid=
 .RS 4
 .TP
 .B uuid=


@@ -114,11 +148,11 @@ created as /dev/mdX, then the minor number X is stored.
 The value is a comma separated list of device names or device name
 patterns.
 Only devices with names which match one entry in the list will be used
 The value is a comma separated list of device names or device name
 patterns.
 Only devices with names which match one entry in the list will be used

-to assemble the array.  Note that the devices 
+to assemble the array.  Note that the devices

 listed there must also be listed on a DEVICE line.
 .TP
 .B level=
 listed there must also be listed on a DEVICE line.
 .TP
 .B level=

-The value is a raid level.  This is not normally used to
+The value is a RAID level.  This is not normally used to

 identify an array, but is supported so that the output of
 
 .B "mdadm \-\-examine \-\-scan"
 identify an array, but is supported so that the output of
 
 .B "mdadm \-\-examine \-\-scan"


@@ -135,6 +169,7 @@ this is mainly for compatibility with the output of
 .TP
 .B spares=
 The value is a number of spare devices to expect the array to have.
 .TP
 .B spares=
 The value is a number of spare devices to expect the array to have.

+The sole use of this keyword and value is as follows:

 .B mdadm \-\-monitor
 will report an array if it is found to have fewer than this number of
 spares when
 .B mdadm \-\-monitor
 will report an array if it is found to have fewer than this number of
 spares when


@@ -150,17 +185,22 @@ the same
 .B spare\-group
 name are considered to be part of the same group.  The significance of
 a group of arrays is that
 .B spare\-group
 name are considered to be part of the same group.  The significance of
 a group of arrays is that

-.B mdadm
+.I mdadm

 will, when monitoring the arrays, move a spare drive from one array in
 a group to another array in that group if the first array had a failed
 or missing drive but no spare.
 
 .TP
 .B auto=
 will, when monitoring the arrays, move a spare drive from one array in
 a group to another array in that group if the first array had a failed
 or missing drive but no spare.
 
 .TP
 .B auto=

-This option declares to
-.B mdadm
-that it should try to create the device file of the array if it
-doesn't already exist, or exists but with the wrong device number.
+This option is rarely needed with mdadm-3.0, particularly if use with
+the Linux kernel v2.6.28 or later.
+It tells
+.I mdadm
+whether to use partitionable array or non-partitionable arrays and,
+in the absence of
+.IR udev ,
+how many partition devices to create.  From 2.6.28 all md array
+devices are partitionable, hence this option is not needed.

 
 The value of this option can be "yes" or "md" to indicate that a
 traditional, non-partitionable md array should be created, or "mdp",
 
 The value of this option can be "yes" or "md" to indicate that a
 traditional, non-partitionable md array should be created, or "mdp",


@@ -189,6 +229,18 @@ Specify the metadata format that the array has.  This is mainly
 recognised for comparability with the output of
 .BR "mdadm \-Es" .
 
 recognised for comparability with the output of
 .BR "mdadm \-Es" .
 

+.TP
+.B container=
+Specify that this array is a member array of some container.  The
+value given can be either a path name in /dev, or a UUID of the
+container array.
+
+.TP
+.B member=
+Specify that this array is a member array of some container.  Each
+type of container has some way to enumerate member arrays, often a
+simple sequence number.  The value identifies which member of a
+container the array is.  It will usually accompany a "container=" word.

 .RE
 
 .TP
 .RE
 
 .TP


@@ -197,15 +249,15 @@ The
 .B mailaddr
 line gives an E-mail address that alerts should be
 sent to when
 .B mailaddr
 line gives an E-mail address that alerts should be
 sent to when

-.M mdadm
+.I mdadm

 is running in
 .B \-\-monitor
 mode (and was given the
 .B \-\-scan
 option).  There should only be one
 .B MAILADDR
 is running in
 .B \-\-monitor
 mode (and was given the
 .B \-\-scan
 option).  There should only be one
 .B MAILADDR

-line and it should have only one address.
-
+line and it should have only one address.  Any subsequent addresses
+are silently ignored.

 
 .TP
 .B MAILFROM
 
 .TP
 .B MAILFROM


@@ -241,8 +293,8 @@ line and it should be give only one program.
 .B CREATE
 The
 .B create
 .B CREATE
 The
 .B create

-line gives default values to be used when creating arrays and device entries for
-arrays.
+line gives default values to be used when creating arrays, new members
+of arrays, and device entries for arrays.

 These include:
 
 .RS 4
 These include:
 
 .RS 4


@@ -287,15 +339,280 @@ or
 Give
 .B symlinks=no
 to suppress this symlink creation.
 Give
 .B symlinks=no
 to suppress this symlink creation.

+
+.TP
+.B names=yes
+Since Linux 2.6.29 it has been possible to create
+.B md
+devices with a name like
+.B md_home
+rather than just a number, like
+.BR md3 .
+.I mdadm
+will use the numeric alternative by default as other tools that interact
+with md arrays may expect only numbers.
+If
+.B names=yes
+is given in
+.I mdadm.conf
+then
+.I mdadm
+will use a name when appropriate.
+If
+.B names=no
+is given, then non-numeric
+.I md
+device names will not be used even if the default changes in a future
+release of
+.IR mdadm .
+
+.TP
+.B bbl=no
+By default,
+.I mdadm
+will reserve space for a bad block list (bbl) on all devices
+included in or added to any array that supports them.  Setting
+.B bbl=no
+will prevent this, so newly added devices will not have a bad
+block log.

 .RE
 
 .RE
 

+.TP
+.B HOMEHOST
+The
+.B homehost
+line gives a default value for the
+.B \-\-homehost=
+option to mdadm.  There should normally be only one other word on the line.
+It should either be a host name, or one of the special words
+.BR <system>,
+.B <none>
+and
+.BR <ignore> .
+If
+.B <system>
+is given, then the
+.BR gethostname ( 2 )
+systemcall is used to get the host name.  This is the default.
+
+If
+.B <ignore>
+is given, then a flag is set so that when arrays are being
+auto-assembled the checking of the recorded
+.I homehost
+is disabled.
+If
+.B <ignore>
+is given it is also possible to give an explicit name which will be
+used when creating arrays.  This is the only case when there can be
+more that one other word on the
+.B HOMEHOST
+line.  If there are other words, or other
+.B HOMEHOST
+lines, they are silently ignored.
+
+If
+.B <none>
+is given, then the default of using
+.BR gethostname ( 2 )
+is over-ridden and no homehost name is assumed.
+
+When arrays are created, this host name will be stored in the
+metadata.  When arrays are assembled using auto-assembly, arrays which
+do not record the correct homehost name in their metadata will be
+assembled using a "foreign" name.  A "foreign" name alway ends with a
+digit string preceded by an underscore to differentiate it
+from any possible local name. e.g.
+.B /dev/md/1_1
+or
+.BR /dev/md/home_0 .
+.TP
+.B AUTO
+A list of names of metadata format can be given, each preceded by a
+plus or minus sign.  Also the word
+.I homehost
+is allowed as is
+.I all
+preceded by plus or minus sign.
+.I all
+is usually last.
+
+When
+.I mdadm
+is auto-assembling an array, either via
+.I \-\-assemble
+or
+.I \-\-incremental
+and it finds metadata of a given type, it checks that metadata type
+against those listed in this line.  The first match wins, where
+.I all
+matches anything.
+If a match is found that was preceded by a plus sign, the auto
+assembly is allowed.  If the match was preceded by a minus sign, the
+auto assembly is disallowed.  If no match is found, the auto assembly
+is allowed.
+
+If the metadata indicates that the array was created for
+.I this
+host, and the word
+.I homehost
+appears before any other match, then the array is treated as a valid
+candidate for auto-assembly.
+
+This can be used to disable all auto-assembly (so that only arrays
+explicitly listed in mdadm.conf or on the command line are assembled),
+or to disable assembly of certain metadata types which might be
+handled by other software.  It can also be used to disable assembly of
+all foreign arrays - normally such arrays are assembled but given a
+non-deterministic name in
+.BR /dev/md/ .
+
+The known metadata types are
+.BR 0.90 ,
+.BR 1.x ,
+.BR ddf ,
+.BR imsm .
+
+.B AUTO
+should be given at most once.  Subsequent lines are silently ignored.
+Thus an earlier config file in a config directory will over-ride
+the setting in a later config file.
+
+.TP
+.B POLICY
+This is used to specify what automatic behavior is allowed on devices
+newly appearing in the system and provides a way of marking spares that can
+be moved to other arrays as well as the migration domains.
+.I Domain
+can be defined through
+.I policy
+line by specifying a domain name for a number of paths from
+.BR /dev/disk/by-path/ .
+A device may belong to several domains. The domain of an array is a union
+of domains of all devices in that array.  A spare can be automatically
+moved from one array to another if the set of the destination array's
+.I domains
+contains all the
+.I domains
+of the new disk or if both arrays have the same
+.IR spare-group .
+
+To update hot plug configuration it is necessary to execute
+.B mdadm \-\-udev\-rules
+command after changing the config file
+
+Keywords used in the
+.I POLICY
+line and supported values are:
+
+.RS 7
+.TP
+.B domain=
+any arbitrary string
+.TP
+.B metadata=
+0.9 1.x ddf or imsm
+.TP
+.B path=
+file glob matching anything from
+.B /dev/disk/by-path
+.TP
+.B type=
+either
+.B disk
+or
+.BR part .
+.TP
+.B action=
+include, re-add, spare, spare-same-slot, or force-spare
+.TP
+.B auto=
+yes, no, or homehost.
+
+.P
+The
+.I action
+item determines the automatic behavior allowed for devices matching the
+.I path
+and
+.I type
+in the same line.  If a device matches several lines with different
+.I  actions
+then the most permissive will apply. The ordering of policy lines
+is irrelevant to the end result.
+.TP
+.B include
+allows adding a disk to an array if metadata on that disk matches that array
+.TP
+.B re\-add
+will include the device in the array if it appears to be a current member
+or a member that was recently removed and the array has a
+write-intent-bitmap to allow the
+.B re\-add
+functionality.
+.TP
+.B spare
+as above and additionally: if the device is bare it can
+become a spare if there is any array that it is a candidate for based
+on domains and metadata.
+.TP
+.B spare\-same\-slot
+as above and additionally if given slot was used by an array that went
+degraded recently and the device plugged in has no metadata then it will
+be automatically added to that array (or it's container)
+.TP
+.B force\-spare
+as above and the disk will become a spare in remaining cases
+.RE
+
+.TP
+.B PART-POLICY
+This is similar to
+.B POLICY
+and accepts the same keyword assignments.  It allows a consistent set
+of policies to applied to each of the partitions of a device.
+
+A
+.B PART-POLICY
+line should set
+.I type=disk
+and identify the path to one or more disk devices.  Each partition on
+these disks will be treated according to the
+.I action=
+setting  from this line.  If a
+.I domain
+is set in the line, then the domain associated with each patition will
+be based on the domain, but with
+.RB \(dq -part N\(dq
+appended, when N is the partition number for the partition that was
+found.
+
+.TP
+.B SYSFS
+The SYSFS line lists custom values of MD device's sysfs attributes which will be
+stored in sysfs after the array is assembled. Multiple lines are allowed and each
+line has to contain the uuid or the name of the device to which it relates.
+.RS 4
+.TP
+.B uuid=
+hexadecimal identifier of MD device. This has to match the uuid stored in the
+superblock.
+.TP
+.B name=
+name of the MD device as was given to
+.I mdadm
+when the array was created. It will be ignored if
+.B uuid
+is not empty.
+.TP
+.RS 7

 
 .SH EXAMPLE
 DEVICE /dev/sd[bcdjkl]1
 .br
 DEVICE /dev/hda1 /dev/hdb1
 
 
 .SH EXAMPLE
 DEVICE /dev/sd[bcdjkl]1
 .br
 DEVICE /dev/hda1 /dev/hdb1
 

-# /dev/md0 is known by its UID.
+# /dev/md0 is known by its UUID.

 .br
 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
 .br
 .br
 ARRAY /dev/md0 UUID=3aaa0122:29827cfa:5331ad66:ca767371
 .br


@@ -328,7 +645,29 @@ ARRAY /dev/md5 uuid=19464854:03f71b1b:e0df2edd:246cc977
 ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b
 .br
            auto=part
 ARRAY /dev/md/home UUID=9187a482:5dde19d9:eea3cc4a:d646ab8b
 .br
            auto=part

-
+.br
+# The name of this array contains a space.
+.br
+ARRAY /dev/md9 name='Data Storage'
+.sp
+POLICY domain=domain1 metadata=imsm path=pci-0000:00:1f.2-scsi-*
+.br
+           action=spare
+.br
+POLICY domain=domain1 metadata=imsm path=pci-0000:04:00.0-scsi-[01]*
+.br
+           action=include
+.br
+# One domain comprising of devices attached to specified paths is defined.
+.br
+# Bare device matching first path will be made an imsm spare on hot plug.
+.br
+# If more than one array is created on devices belonging to domain1 and
+.br
+# one of them becomes degraded, then any imsm spare matching any path for
+.br
+# given domain name can be migrated.
+.br

 MAILADDR root@mydomain.tld
 .br
 PROGRAM /usr/sbin/handle\-mdadm\-events
 MAILADDR root@mydomain.tld
 .br
 PROGRAM /usr/sbin/handle\-mdadm\-events


@@ -336,8 +675,14 @@ PROGRAM /usr/sbin/handle\-mdadm\-events
 CREATE group=system mode=0640 auto=part\-8
 .br
 HOMEHOST <system>
 CREATE group=system mode=0640 auto=part\-8
 .br
 HOMEHOST <system>

+.br
+AUTO +1.x homehost \-all
+.br
+SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000
+.br
+SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4
+sync_speed_max=1000000

 
 .SH SEE ALSO
 .BR mdadm (8),
 .BR md (4).
 
 .SH SEE ALSO
 .BR mdadm (8),
 .BR md (4).

-