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[#1402] Easy editorial changes in the ARM

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Applied several editorial changes in the ARM as a result of the review.
These were mostly little typos and grammatical errors.
This commit is contained in:
Marcin Siodelski 2021-01-07 10:35:25 +01:00
parent 206c5258b4
commit c35917f7cf
1 changed files with 19 additions and 19 deletions
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38
doc/sphinx/arm/hooks-ha.rst
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@ -69,8 +69,8 @@ server synchronizes the database first. The secondary server waits for
the primary server to complete the lease database synchronization before the primary server to complete the lease database synchronization before
it starts the synchronization. it starts the synchronization.
In the hot-standby configuration, one of the servers is also designated In the hot-standby configuration, one of the servers is designated
as "primary" and the second as "standby." However, during normal as "primary" and the other as "standby." However, during normal
operation, the primary server is the only one that responds to DHCP operation, the primary server is the only one that responds to DHCP
requests. The standby server receives lease updates from the primary requests. The standby server receives lease updates from the primary
over the control channel; however, it does not respond to any DHCP over the control channel; however, it does not respond to any DHCP
@ -606,11 +606,11 @@ set the ``max-unacked-clients`` to 0.
The ``delayed-updates-limit`` parameter was introduced in Kea 1.9.4. It The ``delayed-updates-limit`` parameter was introduced in Kea 1.9.4. It
is used to enable or disable the use of the communication recovery is used to enable or disable the use of the communication recovery
procedure and controls server's behavior in the ``communication-recovery`` procedure and controls server's behavior in the ``communication-recovery``
state which were introduced in the same release. This parameter may state which was introduced in the same release. This parameter may
only be used in the load balancing mode. only be used in the load balancing mode.
If the server is in the ``load-balancing`` state and it experiences If the server is in the ``load-balancing`` state and it experiences
communication issues with a partner (heartbeat or lease update fail), communication issues with its partner (heartbeat or lease update fail),
the server transitions to the ``communication-recovery`` state. In this the server transitions to the ``communication-recovery`` state. In this
state the server keeps responding to DHCP queries but it does not send state the server keeps responding to DHCP queries but it does not send
lease updates to the partner. The lease updates are queued until the lease updates to the partner. The lease updates are queued until the
@ -637,27 +637,27 @@ of the same IP addresses or delegated prefixes to different clients
by respective servers. By entering the intermediate ``communication-recovery`` by respective servers. By entering the intermediate ``communication-recovery``
state these problems are avoided. state these problems are avoided.
If the server in the ``communication-recovery`` state re-establishes If a server in the ``communication-recovery`` state re-establishes
communication with the partner, it will try to send all outstanding communication with its partner, it will try to send the partner all
lease updates to it. This is done synchronously and may take considerable of the outstanding lease updates the server has queued. This is done
amount of time before the server transitions to the ``load-balancing`` synchronously and may take considerable amount of time before the server
state and resumes normal operation. The maximum number of lease updates transitions to the ``load-balancing`` state and resumes normal operation.
which can be queued in the ``communication-recovery`` state is controlled The maximum number of lease updates which can be queued in the
by the ``delayed-updates-limit``. If the limit is exceeded, the server ``communication-recovery`` state is controlled by the ``delayed-updates-limit``.
stops queuing lease updates and will perform full database synchronization If the limit is exceeded, the server stops queuing lease updates and
after re-establishing the connection with the partner instead of will perform full database synchronization after re-establishing the
sending outstanding lease updates before transitioning to connection with the partner instead of sending outstanding lease updates
``load-balancing`` state. Even if the limit is exceeded, the server before transitioning to ``load-balancing`` state. Even if the limit is
in the ``communication-recovery`` state remains responsive to the DHCP exceeded, the server in the ``communication-recovery`` state remains
clients. responsive to the DHCP clients.
It is preferred to set higher values of ``delayed-updates-limit`` when It may be preferable to set higher values of ``delayed-updates-limit`` when
there is a risk of prolonged communication interruption between the there is a risk of prolonged communication interruption between the
servers and the lease database is large. This would avoid costly servers and the lease database is large. This would avoid costly
lease database synchronization. On the other hand, if the lease lease database synchronization. On the other hand, if the lease
database is small the time required to send outstanding lease updates database is small the time required to send outstanding lease updates
may be longer than lease database synchronization. In such cases it may be longer than lease database synchronization. In such cases it
may be better to use lower value, e.g. 10. The default value is 100 may be better to use a lower value, e.g. 10. The default value is 100
which seems to be a reasonable compromise and should work well in which seems to be a reasonable compromise and should work well in
most deployments with moderate traffic. most deployments with moderate traffic.