get_info_super: report which other devices are thought to be working/failed.

[thirdparty/mdadm.git] / mdmon.8

diff --git a/mdmon.8 b/mdmon.8
index 8a482b34070af03e3677c6e0afe4b472a8e353aa..2ccb2792766d173f7ffc1f8eb5b8d3e29683ddba 100644 (file)
--- a/mdmon.8
+++ b/mdmon.8
@@ -1,5 +1,5 @@
 .\" See file COPYING in distribution for details.
-.TH MDMON 8 "" v3.1.1
+.TH MDMON 8 "" v3.1.4
 .SH NAME
 mdmon \- monitor MD external metadata arrays
 
@@ -186,6 +186,11 @@ mounted there are special considerations when the root filesystem is
 mounted from an
 .I mdmon
 monitored device.
+Note that in general
+.I mdmon
+is needed even if the filesystem is mounted read-only as some
+filesystems can still write to the device in those circumstances, for
+example to replay a journal after an unclean shutdown.
 
 When the array is assembled by the
 .B initramfs
@@ -195,23 +200,20 @@ as required.  This means that
 .I mdmon
 must be installed on the
 .B initramfs
-and there must be a writable filesystem (typically tmpfs) which
+and there must be a writable filesystem (typically tmpfs) in which
 .B mdmon
 can create a
 .B .pid
 and
 .B .sock
-file on.  The particular filesystem to use is given to mdmon at compile
+file.  The particular filesystem to use is given to mdmon at compile
 time and defaults to
-.BR /lib/init/rw .
+.BR /dev/.mdadm .
 
-This filesystem must persist through to the end of the boot sequence.
+This filesystem must persist through to shutdown time.
 
 After the final root filesystem has be instantiated (usually with
 .BR pivot_root )
-and after
-.B /var
-is mounted writable,
 .I mdmon
 should be run with
 .I "\-\-all \-\-takeover"
@@ -219,20 +221,17 @@ so that the
 .I mdmon
 running from the
 .B initramfs
-can be replaced with one running in the main root.
+can be replaced with one running in the main root, and so the
+memory used by the initramfs can be released.
 
 At shutdown time,
 .I mdmon
 should not be killed along with other processes.  Also as it holds a
 file (socket actually) open in
-.B /var
-it will not be possible to unmount
-.B /var
-if it is a separate filesystem.  Rather the
-.B /var
-filesystem, like the root filesystem, should be remounted read-only.
-
-
+.B /dev
+(by default) it will not be possible to unmount
+.B /dev
+if it is a separate filesystem.
 
 .SH EXAMPLES
 
@@ -241,9 +240,9 @@ filesystem, like the root filesystem, should be remounted read-only.
 Any
 .I mdmon
 which is currently running is killed and a new instance is started.
-This should be run late in the boot sequence and particularly after
-.B /var
-is mounted and writable.
+This should be run during in the boot sequence if an initramfs was
+used, so that any mdmon running from the initramfs will not hold
+the initramfs active.
 .SH SEE ALSO
 .IR mdadm (8),
 .IR md (4).