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diff --git a/man/dmeventd.8_main b/man/dmeventd.8_main new file mode 100644 index 0000000..77b07e4 --- /dev/null +++ b/man/dmeventd.8_main @@ -0,0 +1,179 @@ +.TH DMEVENTD 8 "DM TOOLS #VERSION#" "Red Hat Inc" \" -*- nroff -*- +. +.SH NAME +. +dmeventd \(em Device-mapper event daemon +. +.SH SYNOPSIS +. +.B dmeventd +.RB [ -d +.RB [ -d +.RB [ -d ]]] +.RB [ -f ] +.RB [ -h ] +.RB [ -l ] +.RB [ -R ] +.RB [ -V ] +.RB [ -? ] +. +.SH DESCRIPTION +. +dmeventd is the event monitoring daemon for device-mapper devices. +Library plugins can register and carry out actions triggered when +particular events occur. +. +.SH OPTIONS +. +.TP +.B -d +Repeat from 1 to 3 times +.RB ( -d , +.BR -dd , +.BR -ddd ) +to increase the detail of +debug messages sent to syslog. +Each extra d adds more debugging information. +. +.TP +.B -f +Don't fork, run in the foreground. +. +.TP +.B -h +Show help information. +. +.TP +.B -l +Log through stdout and stderr instead of syslog. +This option works only with option -f, otherwise it is ignored. +. +.TP +.B -? +Show help information on stderr. +. +.TP +.B -R +Replace a running dmeventd instance. The running dmeventd must be version +2.02.77 or newer. The new dmeventd instance will obtain a list of devices and +events to monitor from the currently running daemon. +. +.TP +.B -V +Show version of dmeventd. +. +.SH LVM PLUGINS +. +.TP +.B Mirror +Attempts to handle device failure automatically. +.br +See +.BR lvm.conf (5). +. +.TP +.B Raid +Attempts to handle device failure automatically. +.br +See +.BR lvm.conf (5). +. +.TP +.B Snapshot +Monitors how full a snapshot is becoming and emits a warning to +syslog when it exceeds 80% full. +The warning is repeated when 85%, 90% and 95% of the snapshot is filled. +See +.BR lvm.conf (5). +Snapshot which runs out of space gets invalid and when it is mounted, +it gets umounted if possible. +. +.TP +.B Thin +Monitors how full a thin pool data and metadata is becoming and emits +a warning to syslog when it exceeds 80% full. +The warning is repeated when more then 85%, 90% and 95% +of the thin pool is filled. See +.BR lvm.conf (5). +When a thin pool fills over 50% (data or metadata) thin plugin calls +configured \fBdmeventd/thin_command\fP with every 5% increase. +With default setting it calls internal +\fBlvm lvextend --use-policies\fP to resize thin pool +when it's been filled above configured threshold +\fBactivation/thin_pool_autoextend_threshold\fP. +If the command fails, dmeventd thin plugin will keep +retrying execution with increasing time delay between +retries up to 42 minutes. +User may also configure external command to support more advanced +maintenance operations of a thin pool. +Such external command can e.g. remove some unneeded snapshots, +use \fBfstrim\fP(8) to free recover space in a thin pool, +but also can use \fBlvextend --use-policies\fP if other actions +have not released enough space. +Command is executed with environmental variable +\fBLVM_RUN_BY_DMEVENTD=1\fP so any lvm2 command executed +in this environment will not try to interact with dmeventd. +To see the fullness of a thin pool command may check these +two environmental variables +\fBDMEVENTD_THIN_POOL_DATA\fP and \fBDMEVENTD_THIN_POOL_\:METADATA\fP. +Command can also read status with tools like \fBlvs\fP(8). +. +.TP +.B Vdo +Monitors how full a VDO pool data is becoming and emits +a warning to syslog when it exceeds 80% full. +The warning is repeated when more then 85%, 90% and 95% +of the VDO pool is filled. See +.BR lvm.conf (5). +When a VDO pool fills over 50% vdo plugin calls +configured \fBdmeventd/vdo_command\fP with every 5% increase. +With default setting it calls internal +\fBlvm lvextend --use-policies\fP to resize VDO pool +when it's been filled above the configured threshold +\fBactivation/vdo_pool_autoextend_threshold\fP. +If the command fails, dmeventd vdo plugin will keep +retrying execution with increasing time delay between +retries up to 42 minutes. +User may also configure external command to support more advanced +maintenance operations of a VDO pool. +Such external command can e.g. remove some unneeded space +with \fBfstrim\fP(8), +but also can use \fBlvextend --use-policies\fP if other actions +have not released enough space. +Command is executed with environmental variable +\fBLVM_RUN_BY_DMEVENTD=1\fP so any lvm2 command executed +in this environment will not try to interact with dmeventd. +To see the fullness of a VDO pool command may check this +environmental variable \fBDMEVENTD_VDO_POOL\fP. +Command can also read status with tools like \fBlvs\fP(8). +. +.SH ENVIRONMENT VARIABLES +. +.TP +.B DMEVENTD_THIN_POOL_DATA +Variable is set by thin plugin and is available to executed program. Value present +actual usage of thin pool data volume. Variable is not set when error event +is processed. +.TP +.B DMEVENTD_THIN_POOL_METADATA +Variable is set by thin plugin and is available to executed program. Value present +actual usage of thin pool metadata volume. Variable is not set when error event +is processed. +.TP +.B DMEVENTD_VDO_POOL +Variable is set by vdo plugin and is available to executed program. Value present +actual usage of VDO pool data volume. Variable is not set when error event +is processed. +.TP +.B LVM_RUN_BY_DMEVENTD +Variable is set by thin and vdo plugin to prohibit recursive interaction +with dmeventd by any executed lvm2 command from +a thin_command, vdo_command environment. +. +.SH SEE ALSO +. +.BR lvm (8), +.BR lvm.conf (5), +.BR lvextend (8), +.br +.BR fstrim (8) |