Allow autoassembly to choose it's own name for the array.

[thirdparty/mdadm.git] / mdadm.8

diff --git a/mdadm.8 b/mdadm.8
index e3052dcd967c5bbdc49342efa7da179fa44880e4..a3d9dc53b0bdb134faeb2ddce7b55f4309087941 100644 (file)
--- a/mdadm.8
+++ b/mdadm.8
@@ -79,7 +79,7 @@ provides a layer over a true device that can be used to inject faults.
 '''the
 '''.B raidtools
 '''configuration file, at all.  It has a different configuration file
-'''with a different format and an different purpose.
+'''with a different format and a different purpose.
 
 .SH MODES
 mdadm has 7 major modes of operation:
@@ -398,12 +398,20 @@ and "flush" will clear any persistent faults.
 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
+Finally, the layout options for RAID10 are one of 'n', 'o' 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
+signals 'near' copies. Multiple copies of one data block are at
+similar offsets in different devices.
+
+.I o
+signals 'offset' copies.  Rather than the chunks being duplicated
+within a stripe, whole stripes are duplicated but are rotated by one
+device so duplicate blocks are on different devices.  Thus subsequent
+copies of a block are in the next drive, and are one chunk further
+down.
+
 .I f
 signals 'far' copies
 (multiple copies have very different offsets).  See md(4) for more
@@ -439,11 +447,12 @@ slash ('/') if it is a real file (not 'internal' or 'none').
 Note: external bitmaps are only known to work on ext2 and ext3.
 Storing bitmap files on other filesystems may result in serious problems.
 
-
 .TP
 .BR --bitmap-chunk=
 Set the chunksize of the bitmap. Each bit corresponds to that many
-Kilobytes of storage. Default is 4 when using a file based bitmap.
+Kilobytes of storage.
+When using a file based bitmap, the default is to use the smallest
+size that is atleast 4 and requires no more than 2^21 chunks.
 When using an
 .B internal
 bitmap, the chunksize is automatically determined to make best use of
@@ -586,7 +595,11 @@ will look for super blocks with a minor number of 0.
 .TP
 .BR -N ", " --name=
 Specify the name of the array to assemble.  This must be the name
-that was specified when creating the array.
+that was specified when creating the array.  It must either match
+then name stored in the superblock exactly, or it must match
+which the current
+.I homehost
+is added to the start of the given name.
 
 .TP
 .BR -f ", " --force
@@ -594,14 +607,25 @@ Assemble the array even if some superblocks appear out-of-date
 
 .TP
 .BR -R ", " --run
-Attempt to start the array even if fewer drives were given than are
-needed for a full array. Normally if not all drives are found and
+Attempt to start the array even if fewer drives were given than were
+present last time the array was active.  Normally if not all the
+expected drives are found and
 .B --scan
 is not used, then the array will be assembled but not started.
 With
 .B --run
 an attempt will be made to start it anyway.
 
+.TP
+.B --no-degraded
+This is the reverse of
+.B --run
+in that it inhibits the started if array unless all expected drives
+are present.  This is only needed with
+.B --scan
+and can be used if you physical connections to devices are
+not as reliable as you would like.
+
 .TP
 .BR -a ", " "--auto{=no,yes,md,mdp,part}"
 See this option under Create and Build options.
@@ -630,6 +654,8 @@ argument given to this flag can be one of
 .BR sparc2.2 ,
 .BR summaries ,
 .BR uuid ,
+.BR name ,
+.BR homehost ,
 .BR resync ,
 .BR byteorder ,
 or
@@ -661,6 +687,21 @@ option will change the uuid of the array.  If a UUID is given with the
 be used to help identify the devices in the array.
 If no "--uuid" is given, a random uuid is chosen.
 
+The
+.B name
+option will change the
+.I name
+of the array as stored in the superblock.  This is only supported for
+version-1 superblocks.
+
+The
+.B homehost
+option will change the
+.I homehost
+as recorded in the superblock.  For version-0 superblocks, this is the
+same as updating the UUID.
+For version-1 superblocks, this involves updating the name.
+
 The
 .B resync
 option will cause the array to be marked
@@ -1295,7 +1336,7 @@ 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.
+device has been successfully rebuilt and has been made active.
 (syslog priority: Info)
 
 .TP