diff options
author | Bryn M. Reeves <bmr@redhat.com> | 2016-12-17 16:41:00 +0000 |
---|---|---|
committer | Bryn M. Reeves <bmr@redhat.com> | 2017-03-08 17:44:04 +0000 |
commit | c51203760c8958f81344d1e03fe824818f632ee0 (patch) | |
tree | 3e8e7c3d96981fcfb6428d44edd8863e97f36ef6 | |
parent | 9edf67759ca046ad4a14a4ae33db647323535df1 (diff) | |
download | lvm2-c51203760c8958f81344d1e03fe824818f632ee0.tar.gz |
man: add dmfilemapd options to dmstats.8.in
Add descriptions of --follow and --nomonitor, and the behaviour
of create and update_filemap when starting dmfilemapd.
-rw-r--r-- | man/dmstats.8.in | 85 |
1 files changed, 80 insertions, 5 deletions
diff --git a/man/dmstats.8.in b/man/dmstats.8.in index ba828dc4a..b9bc781bf 100644 --- a/man/dmstats.8.in +++ b/man/dmstats.8.in @@ -14,6 +14,9 @@ . RB [ \-\-region ] . RB [ \-\-group ] .. +.de OPT_FOREGROUND +. RB [ \-\-foreground ] +.. . .\" Print units suffix, use with arg to print human .\" man2html can't handle too many changes per command @@ -89,6 +92,10 @@ dmstats \(em device-mapper statistics management . RB [ \-\-bounds . IR \%histogram_boundaries ] . RB [ \-\-filemap ] +. RB [ \-\-follow +. IR follow_mode ] +. OPT_FOREGROUND +. RB [ \-\-nomonitor ] . RB [ \-\-nogroup ] . RB [ \-\-precise ] . RB [ \-\-start @@ -215,6 +222,9 @@ dmstats \(em device-mapper statistics management . IR file_path . RB [ \-\-groupid . IR id ] +. RB [ \-\-follow +. IR follow_mode ] +. OPT_FOREGROUND . ad b .. .CMD_UPDATE_FILEMAP @@ -314,6 +324,60 @@ create regions corresponding to the locations of the on-disk extents allocated to the file(s). . .HP +.BR \-\-nomonitor +.br +Disable the \fBdmfilemapd\fP daemon when creating new file mapped +groups. Normally the device-mapper filemap monitoring daemon, +\fBdmfilemapd\fP, is started for each file mapped group to update the +set of regions as the file changes on-disk: use of this option +disables this behaviour. + +Regions in the group may still be updated with the +\fBupdate_filemap\fP command, or by starting the daemon manually. +. +.HP +.BR \-\-follow +.IR follow_mode +.br +Specify the \fBdmfilemapd\fP file following mode. The file map +monitoring daemon can monitor files in two distinct ways: the mode +affects the behaviour of the daemon when a file under monitoring is +renamed or unlinked, and the conditions which cause the daemon to +terminate. + +The \fBfollow_mode\fP argument is either "inode", for follow-inode +mode, or "path", for follow-path. + +If follow-inode mode is used, the daemon will hold the file open, and +continue to update regions from the same file descriptor. This means +that the mapping will follow rename, move (within the same file +system), and unlink operations. This mode is useful if the file is +expected to be moved, renamed, or unlinked while it is being +monitored. + +In follow-inode mode, the daemon will exit once it detects that the +file has been unlinked and it is the last holder of a reference to it. + +If follow-path is used, the daemon will re-open the provided path on +each monitoring iteration. This means that the group will be updated +to reflect a new file being moved to the same path as the original +file. This mode is useful for files that are expected to be updated +via unlink and rename. + +In follow-path mode, the daemon will exit if the file is removed and +not replaced within a brief tolerance interval. + +In either mode, the daemon exits automatically if the monitored group +is removed. +. +.HP +.BR \-\-foreground +.br +Specify that the \fBdmfilemapd\fP daemon should run in the foreground. +The daemon will not fork into the background, and will replace the +\fBdmstats\fP command that started it. +. +.HP .BR \-\-groupid .IR id .br @@ -568,6 +632,11 @@ By default regions that map a file are placed into a group and the group alias is set to the basename of the file. This behaviour can be overridden with the \fB\-\-alias\fP and \fB\-\-nogroup\fP options. +Creating a group that maps a file automatically starts a daemon, +\fBdmfilemapd\fP to monitor the file and update the mapping as the +extents allocated to the file change. This behaviour can be disabled +using the \fB\-\-nomonitor\fP option. + Use the \fB\-\-group\fP option to only display information for groups when listing and reporting. . @@ -678,17 +747,23 @@ The group to be removed is specified using \fB\-\-groupid\fP. .CMD_UPDATE_FILEMAP .br Update a group of \fBdmstats\fP regions specified by \fBgroup_id\fP, -that were previously created with \fB\-\-filemap\fP. This will add -and remove regions to reflect changes in the allocated extents of -the file on-disk, since the time that it was crated or last updated. +that were previously created with \fB\-\-filemap\fP, either directly, +or by starting the monitoring daemon, \fBdmfilemapd\fP. + +This will add and remove regions to reflect changes in the allocated +extents of the file on-disk, since the time that it was crated or last +updated. Use of this command is not normally needed since the \fBdmfilemapd\fP daemon will automatically monitor filemap groups and perform these updates when required. -If a filemapped group was created with \fB\-\-nominitor\fP, or the +If a filemapped group was created with \fB\-\-nomonitor\fP, or the daemon has been killed, the \fBupdate_filemap\fP can be used to -manually force an update. +manually force an update or start a new daemon. + +Use \fB\-\-nomonitor\fP to force a direct update and disable starting +the monitoring daemon. . .SH REGIONS, AREAS, AND GROUPS . |