Use this documentation with care! It describes
the outdated version 7, which was actively
developed around 2014 and is considered dead by the
This documentation reflects the latest update of the v7-stable branch. It describes the 7.6.8 version, which was never released. As such, it contains some content that does not apply to any released version.
To obtain the doc that properly matches your installed v7 version, obtain the doc set from your distro. Each version of rsyslog contained the version that exactly matches it.
As general advise, it is strongly suggested to upgrade to the current version supported by the rsyslog project. The current version can always be found on the right-hand side info box on the rsyslog web site.
Note that there is only limited rsyslog community support available for the outdated v7 version (officially we do not support it at all, but we usually are able to answer simple questions). If you need to stick with v7, it probably is best to ask your distribution for support.
General Queue Parameters¶
Queue parameters can be used together with the following statements:
Queues need to be configured in the action or ruleset it should affect. If nothing is configured, default values will be used. Thus, the default ruleset has only the default main queue. Specific Action queues are not set up by default.
To fully understand queue parameters and how they interact, be sure to read the queues documentation.
queue.filename name File name to be used for the queue files. Please note that this is actually just the file name. A directory can NOT be specified in this paramter. If the files shall be created in a specific directory, specify queue.spoolDirectory for this. The filename is used to build to complete path for queue files.
queue.spoolDirectory name This is the directory into which queue files will be stored. Note that the directory must exist, it is NOT automatically created by rsyslog. If no spoolDirectory is specified, the work directory is used.
queue.size number This is the maximum size of the queue in number of messages. Note that setting the queue size to very small values (roughly below 100 messages) is not supported and can lead to unpredictable results. For more information on the current status of this restriction see the rsyslog FAQ: “lower bound for queue sizes”.
queue.dequeuebatchsize number default 16
queue.maxdiskspace number The maximum size that all queue files together will use on disk. Note that the actual size may be slightly larger than the configured max, as rsyslog never writes partial queue records.
queue.highwatermark number This applies to disk-assisted queues, only. When the queue fills up to this number of messages, the queue begins to spool messages to disk. Please note that this should note happen as part of usual processing, because disk queue mode is very considerably slower than in-memory queue mode. Going to disk should be reserved for cases where an output action destination is offline for some period.
queue.lowwatermark number default 2000
queue.fulldelaymark number Number of messages when the queue should block delayable messages. Messages are NO LONGER PROCESSED until the queue has sufficient space again. If a message is delayable depends on the input. For example, messages received via imtcp are delayable (because TCP can push back), but those received via imudp are not (as UDP does not permit a push back). The intent behind this setting is to leave some space in an almost-full queue for non-delayable messages, which would be lost if the queue runs out of space. Please note that if you use a DA queue, setting the fulldelaymark ABOVE the highwatermark makes the queue never activate disk mode for delayable inputs. So this is probably not what you want.
queue.discardmark number default 9750]
queue.discardseverity number *numerical* severity! default 8 (nothing discarded)
queue.checkpointinterval number Disk queues by default do not update housekeeping structures every time the queue writes to disk. This is for performance reasons. In the event of failure, data will still be lost (except when data is mangled via the file structures). However, disk queues can be set to write bookkeeping information on checkpoints (every n records), so that this can be made ultra-reliable, too. If the checkpoint interval is set to one, no data can be lost, but the queue is exceptionally slow.
queue.syncqueuefiles on/off (default “off”)
Disk-based queues can be made very reliable by issuing a (f)sync after each write operation. This happens when you set the parameter to “on”. Activating this option has a performance penalty, so it should not be turned on without a good reason. Note that the penalty also depends on queue.checkpointInterval frequency.
queue.workerthreads number number of worker threads, default 1, recommended 1
queue.timeoutshutdown number number is timeout in ms (1000ms is 1sec!), default 0 (indefinite)
queue.timeoutactioncompletion number number is timeout in ms (1000ms is 1sec!), default 1000, 0 means immediate!
queue.timeoutenqueue number number is timeout in ms (1000ms is 1sec!), default 2000, 0 means discard immediate
queue.timeoutworkerthreadshutdown number number is timeout in ms (1000ms is 1sec!), default 60000 (1 minute)
queue.workerthreadminimummessages number default 100
queue.maxfilesize size_nbr default 1m
queue.dequeueslowdown number number is timeout in microseconds (1000000us is 1sec!), default 0 (no delay). Simple rate-limiting!
The following is a sample of a TCP forwarding action with its own queue.
action(type="omfwd" target="192.168.2.11" port="10514" protocol="tcp" queue.filename="forwarding" queue.size="1000000" queue.type="LinkedList" )