.\" -*- nroff -*-
-.TH MDADM 8 "" v2.0-devel-3
+.TH MDADM 8 "" v2.2
.SH NAME
mdadm \- manage MD devices
.I aka
.BR RAID4 ,
.BR RAID5 ,
.BR RAID6 ,
+.BR RAID10 ,
.BR MULTIPATH ,
and
.BR FAULTY .
.TP
.B "Follow or Monitor"
Monitor one or more md devices and act on any state changes. This is
-only meaningful for raid1, 4, 5, 6 or multipath arrays as
+only meaningful for raid1, 4, 5, 6, 10 or multipath arrays as
only these have interesting state. raid0 or linear never have
missing, spare, or failed drives, so there is nothing to monitor.
Set raid level. When used with
.IR --create ,
options are: linear, raid0, 0, stripe, raid1, 1, mirror, raid4, 4,
-raid5, 5, raid6, 6, multipath, mp, fautly. Obviously some of these are synonymous.
+raid5, 5, raid6, 6, raid10, 10, multipath, mp, fautly. Obviously some of these are synonymous.
When used with
.IR --build ,
only linear, stripe, raid0, 0, raid1, multipath, mp, and faulty are valid.
.TP
-.BR -p ", " --parity=
-Set raid5 parity algorithm. Options are:
+.BR -p ", " --layout=
+This option configures the fine details of data layout for raid5,
+and raid10 arrays, and controls the failure modes for
+.IR faulty .
+
+The layout of the raid5 parity block can be one of
left-asymmetric,
left-symmetric,
right-asymmetric,
right-symmetric,
la, ra, ls, rs. The default is left-symmetric.
-This option is also used to set the failure mode for
-.IR faulty .
-The options are:
+When setting the failure mode for
+.I faulty
+the options are:
write-transient,
wt,
read-transient,
To set the parity with "--grow", the level of the array ("faulty")
must be specified before the fault mode is specified.
+Finally, the layout options for RAID10 are either 'n' or 'p' followed
+by a small number. The default is 'n2'.
+
+.I n
+signals 'near' copies (multiple copies of one data block are at
+similar offsets in different devices) while
+.I f
+signals 'far' copies
+(multiple copies have very different offsets). See md(4) for more
+detail about 'near' and 'far'.
+
+The number is the number of copies of each datablock. 2 is normal, 3
+can be useful. This number can be at most equal to the number of
+devices in the array. It does not need to divide evenly into that
+number (e.g. it is perfectly legal to have an 'n2' layout for an array
+with an odd number of devices).
+
.TP
-.BR --layout=
-same as --parity
+.BR --parity=
+same as --layout (thus explaining the p of
+.IR -p ).
.TP
.BR -b ", " --bitmap=
.BR --assume-clean
Tell
.I mdadm
-that the array pre-existed and is known to be clean. This is only
-really useful for Building RAID1 array. Only use this if you really
-know what you are doing. This is currently only supported for --build.
+that the array pre-existed and is known to be clean. It can be useful
+when trying to recover from a major failure as you can be sure that no
+data will be affected unless you actually write to the array. It can
+also be used when creating a RAID1 or RAID10 if you want to avoid the
+initial resync, however this practice - while normally safe - is not
+recommended. Use this ony if you really know what you are doing.
.TP
.BR -N ", " --name=
Instruct mdadm to create the device file if needed, possibly allocating
an unused minor number. "md" causes a non-partitionable array
to be used. "mdp", "part" or "p" causes a partitionable array (2.6 and
-later) to be used. "yes" requires the named md device to have a
-'standard' format, and the type and minor number will be determined
+later) to be used. "yes" requires the named md device to haveo
+a 'standard' format, and the type and minor number will be determined
from this. See DEVICE NAMES below.
The argument can also come immediately after
argument given to this flag can be one of
.BR sparc2.2 ,
.BR summaries ,
+.BR uuid ,
.BR resync ,
.BR byteorder ,
or
The
.B sparc2.2
-option will adjust the superblock of an array what was created on a Sparc
+option will adjust the superblock of an array what was created on a Sparc
machine running a patched 2.2 Linux kernel. This kernel got the
alignment of part of the superblock wrong. You can use the
.B "--examine --sparc2.2"
assembled. This is not needed on 2.6 and later kernels as they make
this adjustment automatically.
+The
+.B uuid
+option will change the uuid of the array. If a UUID is given with the
+"--uuid" option that UUID will be used as a new UUID and with
+.B NOT
+be used to help identify the devices in the array.
+If no "--uuid" is given, a random uuid is chosen.
+
The
.B resync
option will cause the array to be marked
.BR -p ", " --program ", " --alert
Give a program to be run whenever an event is detected.
+.TP
+.BR -y ", " --syslog
+Cause all events to be reported through 'syslog'. The messages have
+facility of 'daemon' and varying priorities.
+
.TP
.BR -d ", " --delay
Give a delay in seconds.
is not given and insufficient drives were listed to start a complete
(non-degraded) array, then the array is not started (to guard against
usage errors). To insist that the array be started in this case (as
-may work for RAID1, 4, 5 or 6), give the
+may work for RAID1, 4, 5, 6, or 10), give the
.B --run
flag.
.TP
.B DeviceDisappeared
An md array which previously was configured appears to no longer be
-configured.
+configured. (syslog priority: Critical)
If
.I mdadm
.TP
.B RebuildStarted
-An md array started reconstruction.
+An md array started reconstruction. (syslog priority: Warning)
.TP
.BI Rebuild NN
Where
.I NN
is 20, 40, 60, or 80, this indicates that rebuild has passed that many
-percentage of the total.
+percentage of the total. (syslog priority: Warning)
.TP
.B RebuildFinished
An md array that was rebuilding, isn't any more, either because it
-finished normally or was aborted.
+finished normally or was aborted. (syslog priority: Warning)
.TP
.B Fail
-An active component device of an array has been marked as faulty.
+An active component device of an array has been marked as
+faulty. (syslog priority: Critical)
.TP
.B FailSpare
A spare component device which was being rebuilt to replace a faulty
-device has failed.
+device has failed. (syslog priority: Critial)
.TP
.B SpareActive
A spare component device which was being rebuilt to replace a faulty
device as been successfully rebuild and has been made active.
+(syslog priority: Info)
.TP
.B NewArray
A new md array has been detected in the
.B /proc/mdstat
-file.
+file. (syslog priority: Info)
.TP
.B DegradedArray
notices a drive failure which causes degradation, but only when
.I mdadm
notices that an array is degraded when it first sees the array.
+(syslog priority: Critial)
.TP
.B MoveSpare
A spare drive has been moved from one array in a
.B spare-group
to another to allow a failed drive to be replaced.
+(syslog priority: Info)
.TP
.B SparesMissing
array, it will report a
.B SparesMissing
message.
+(syslog priority: Info)
.TP
.B TestMessage
An array was found at startup, and the
.B --test
flag was given.
+(syslog priority: Info)
.RE
Only
projects / thirdparty / mdadm.git / blobdiff