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Man pages: updates for container etc. 

Multiple updates to try to get up to date with current code.

Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2008-11-05 17:03:51 +11:00
parent d49410d3ab
commit 8fd8d9c41d
2 changed files with 196 additions and 63 deletions
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224
mdadm.8
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@ -52,7 +52,9 @@ is also not true RAID, and it only involves one device. It
provides a layer over a true device that can be used to inject faults.
B CONTAINER
is different again. A CONTAINER is a collection of devices that are
is different again. A
.B CONTAINER
is a collection of devices that are
managed as a set. This is similar to the set of devices connected to
a hardware RAID controller. The set of devices may contain a number
of different RAID arrays each utilising some (or all) blocks from a
@ -61,7 +63,15 @@ might form a RAID1 used the whole devices. The remaining three might
have a RAID5 over the first half of each device, and a RAID0 over the
second half.
With a CONTAINER, there is one set of metadata the describes
With a
.BR CONTAINER ,
there is one set of metadata that describes all of
the arrays in the container. So when
.I mdadm
creates a
.B CONTAINER
device, it just represents the metadata. Other normal arrays (RAID1
etc) can be created inside that container.
.\".I mdadm
@ -153,6 +163,13 @@ This provides a convenient interface to a
system. As each device is detected,
.I mdadm
has a chance to include it in some array as appropriate.
.P
If a
.B CONTAINER
is passed to
.I mdadm
in this mode, then any arrays within that container will be assembled
and started.
.TP
.B Manage
@ -286,10 +303,12 @@ If the config file given is
then nothing will be read, but
.I mdadm
will act as though the config file contained exactly
.B "DEVICE partitions"
.B "DEVICE partitions containers"
and will read
.B /proc/partitions
to find a list of devices to scan.
to find a list of devices to scan, and
.B /proc/mdstat
to find a list of containers to examine.
If the word
.B "none"
is given for the config file, then
@ -339,6 +358,15 @@ Use the new version-1 format superblock. This has few restrictions.
The different sub-versions store the superblock at different locations
on the device, either at the end (for 1.0), at the start (for 1.1) or
4K from the start (for 1.2).
.IP ddf
Use the "Industry Standard" DDF (Disk Data Format) format. When
creating a DDF array a
.B CONTAINER
will be created, and normal arrays can be created in that container.
.IP imsm
Use the Intel Matrix Storage Manager metadata format. This creates a
.B CONTAINER
which is managed in a similar manner to DDF.
.RE
.TP
@ -411,6 +439,10 @@ The size can be given as
.B max
which means to choose the largest size that fits on all current drives.
This value can not be used with
.B CONTAINER
metadata such as DDF and IMSM.
.TP
.BR \-c ", " \-\-chunk=
Specify chunk size of kibibytes. The default is 64.
@ -424,7 +456,14 @@ Specify rounding factor for linear array (==chunk size)
Set raid level. When used with
.BR \-\-create ,
options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4,
raid5, 5, raid6, 6, raid10, 10, multipath, mp, faulty. Obviously some of these are synonymous.
raid5, 5, raid6, 6, raid10, 10, multipath, mp, faulty, container.
Obviously some of these are synonymous.
When a
.B CONTAINER
metadata type is requested, only the
.B container
level is permitted, and it does not need to be explicitly given.
When used with
.BR \-\-build ,
@ -647,9 +686,9 @@ partitions. A different number of partitions can be specified at the
end of this option (e.g.
.BR \-\-auto=p7 ).
If the device name ends with a digit, the partition names add a 'p',
and a number, e.g. "/dev/home1p3". If there is no
and a number, e.g. "/dev/md/home1p3". If there is no
trailing digit, then the partition names just have a number added,
e.g. "/dev/scratch3".
e.g. "/dev/md/scratch3".
If the md device name is in a 'standard' format as described in DEVICE
NAMES, then it will be created, if necessary, with the appropriate
@ -657,29 +696,30 @@ number based on that name. If the device name is not in one of these
formats, then a unused minor number will be allocated. The minor
number will be considered unused if there is no active array for that
number, and there is no entry in /dev for that number and with a
non-standard name.
.TP
.BR \-\-symlink = no
Normally when
.B \-\-auto
causes
.I mdadm
to create devices in
.B /dev/md/
it will also create symlinks from
.B /dev/
with names starting with
.B md
or
.BR md_ .
Use
.B \-\-symlink=no
to suppress this, or
.B \-\-symlink=yes
to enforce this even if it is suppressing
.IR mdadm.conf .
non-standard name. Name that are not in 'standard' format are only
allowed in "/dev/md/".
\".TP
\".BR \-\-symlink = no
\"Normally when
\".B \-\-auto
\"causes
\".I mdadm
\"to create devices in
\".B /dev/md/
\"it will also create symlinks from
\".B /dev/
\"with names starting with
\".B md
\"or
\".BR md_ .
\"Use
\".B \-\-symlink=no
\"to suppress this, or
\".B \-\-symlink=yes
\"to enforce this even if it is suppressing
\".IR mdadm.conf .
\"
.SH For assemble:
@ -1166,7 +1206,8 @@ the first device given is the md device.
In the second usage example, all devices listed are treated as md
devices and assembly is attempted.
In the third (where no devices are listed) all md devices that are
listed in the configuration file are assembled.
listed in the configuration file are assembled. Then any arrays that
can be found on unused devices will also be assembled.
If precisely one device is listed, but
.B \-\-scan
@ -1196,6 +1237,8 @@ or requested with (a possibly implicit)
.BR \-\-scan .
In the later case,
.B /etc/mdadm.conf
or
.B /etc/mdadm/mdadm.conf
is used.
If
@ -1260,16 +1303,13 @@ and no devices are listed,
will first attempt to assemble all the arrays listed in the config
file.
If a
.B homehost
has been specified (either in the config file or on the command line),
.I mdadm
will look further for possible arrays and will try to assemble
anything that it finds which is tagged as belonging to the given
homehost. This is the only situation where
.I mdadm
will assemble arrays without being given specific device name or
identity information for the array.
It will then look further for possible arrays and will try to assemble
anything that it finds. Arrays which are tagged as belonging to the given
homehost will be assembled and started normally. Arrays which do not
obviously belong to this host are given names that are expected not to
conflict with anything local, and are started "read-auto" so that
nothing is written to any device until the array is written to. i.e.
automatic resync etc is delayed.
If
.I mdadm
@ -1425,6 +1465,16 @@ setting.
.\".B \-\-size
.\"is given, the apparent size of the smallest drive given is used.
When creating an array within a
.B CONTAINER
.I mdadm
can be given either the list of devices to use, or simply the name of
the container. The former case gives control over which devices in
the container will be used for the array. The latter case allows
.I mdadm
to automatically choose which devices to use based on how much spare
space is available.
The General Management options that are valid with
.B \-\-create
are:
@ -1773,6 +1823,10 @@ add a write-intent bitmap to any array which supports these bitmaps, or
remove a write-intent bitmap from such an array.
.PP
GROW mode is not currently supported for
.B CONTAINERS
or arrays inside containers.
.SS SIZE CHANGES
Normally when an array is built the "size" it taken from the smallest
of the drives. If all the small drives in an arrays are, one at a
@ -1851,6 +1905,13 @@ passed to
.B "mdadm \-\-incremental"
to be conditionally added to an appropriate array.
If the device passed is a
.B CONTAINER
device created by a previous call to
.IR mdadm ,
then rather than trying to add that device to an array, all the arrays
described by the metadata of the container will be started.
.I mdadm
performs a number of tests to determine if the device is part of an
array, and which array it should be part of. If an appropriate array
@ -1864,14 +1925,6 @@ will only add devices to an array which were previously working
(active or spare) parts of that array. It does not currently support
automatic inclusion of a new drive as a spare in some array.
.B "mdadm \-\-incremental"
requires a bug-fix in all kernels through 2.6.19.
Hopefully, this will be fixed in 2.6.20; alternately, apply the patch
which is included with the mdadm source distribution. If
.I mdadm
detects that this bug is present, it will abort any attempt to use
.BR \-\-incremental .
The tests that
.I mdadm
makes are as follow:
@ -1985,6 +2038,19 @@ operates.
Setting this value to 1 will prevent mdadm from automatically launching
mdmon. This variable is intended primarily for debugging mdadm/mdmon.
.TP
.B MDADM_NO_UDEV
Normally,
.I mdadm
does not create any device nodes in /dev, but leaves that task to
.IR udev .
If
.I udev
appears not to be configured, or if this environment variable is set
to '1', the
.I mdadm
will create and devices that are needed.
.SH EXAMPLES
.B " mdadm \-\-query /dev/name-of-device"
@ -2075,6 +2141,24 @@ can be started.
Any devices which are components of /dev/md4 will be marked as faulty
and then remove from the array.
.B " mdadm --create /dev/md/ddf --metadata=ddf --raid-disks 6 /dev/sd[a-f]"
.br
Create a DDF array over 6 devices.
.B " mdadm --create /dev/md/home -n3 -l5 -z 30000000 /dev/md/ddf"
.br
Create a raid5 array over any 3 devices in the given DDF set. Use
only 30 gigabytes of each device.
.B " mdadm -A /dev/md/ddf1 /dev/sd[a-f]"
.br
Assemble a pre-exist ddf array.
.B " mdadm -I /dev/md/ddf1"
.br
Assemble all arrays contained in the ddf array, assigning names as
appropriate.
.B " mdadm \-\-create \-\-help"
.br
Provide help about the Create mode.
@ -2124,29 +2208,51 @@ is used instead.
.SH DEVICE NAMES
While entries in the /dev directory can have any format you like,
.I mdadm
has an understanding of 'standard' formats which it uses to guide its
behaviour when creating device files via the
.B \-\-auto
option.
understand two sorts of names for array devices.
The first is the so-called 'standard' format name, which matches the
names used by the kernel and which appear in
.IR /proc/mdstat .
The second sort can be freely chosen, but must reside in
.IR /dev/md/ .
When giving a device name to
.I mdadm
to create or assemble an array, either full path name such as
.I /dev/md0
or
.I /dev/md/home
can be given, or just the suffix of the second sort of name, such as
.I home
can be given.
When
.I mdadm
chooses device names during auto-assembly, it will normally add a
small sequence number to the end of the name to avoid conflicted
between multiple arrays that have the same name. If
.I mdadm
can reasonably determine that the array really is meant for this host,
either by a hostname in the metadata, or by the presence of the array
in /etc/mdadm.conf, then it will leave of the suffix if possible.
The standard names for non-partitioned arrays (the only sort of md
array available in 2.4 and earlier) are either of
array available in 2.4 and earlier) are of the form
.IP
/dev/mdNN
.br
/dev/md/NN
.PP
where NN is a number.
The standard names for partitionable arrays (as available from 2.6
onwards) are either of
onwards) are of the form
.IP
/dev/md/dNN
.br
/dev/md_dNN
.PP
Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2".
.PP
From kernel version, 2.6.28 the "non-partitioned array" can actually
be partitioned. So the "md_dNN" names are no longer needed, and
partitions such as "/dev/mdNNpXX" are possible.
.SH NOTE
.I mdadm

35
mdadm.conf.5
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@ -53,9 +53,20 @@ Also, there may be several device lines present in the file.
Alternatively, a
.B device
line can contain the word
line can contain either of both of the words
.B containers
and
.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.
.PP
The word
.I partitions
will cause
.I mdadm
to read
.I /proc/partitions
@ -67,7 +78,7 @@ but only the major and minor device numbers. It scans
.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
@ -82,9 +93,13 @@ 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
.BR /dev/md1 .
If no device name is given,
.I mdadm
will use various heuristic to determine an appropriate name.
.PP
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
@ -189,6 +204,18 @@ Specify the metadata format that the array has. This is mainly
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.
.IP
.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