From: Thomas Markwalder Date: Wed, 22 Sep 2021 16:11:27 +0000 (-0400) Subject: [#2085] Added discussion to ARM per review X-Git-Tag: Kea-2.0.0~67 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1253332e9e5174f2d61aa0c24cf459c7785c412;p=thirdparty%2Fkea.git [#2085] Added discussion to ARM per review doc/sphinx/arm/hooks-ha.rst - added a note to passive backup section discussing queue lengths and warning. --- diff --git a/doc/sphinx/arm/hooks-ha.rst b/doc/sphinx/arm/hooks-ha.rst index 9f3d6ed9b5..37f7bc9768 100644 --- a/doc/sphinx/arm/hooks-ha.rst +++ b/doc/sphinx/arm/hooks-ha.rst @@ -1076,6 +1076,25 @@ is more important than consistency of the lease information between the primary and the backups, and in all cases when the DHCP service latency should be minimal. +.. note:: + + Currently, active servers place lease updates to be sent to peers onto internal + queues (one queue per peer/URL). In passive-backup mode, active servers do not + wait for lease udpates to be acknowledged thus during times of heavy client + traffic it is possible for the number of lease updates queued for transimission + to accumulate faster than they can be delivered. As client traffic lessens the + queues begin to empty. As of Kea 2.0.0, active servers monitor the size of + these queues and will emit periodic warnings (see HTTP_CILENT_QUEUE_SIZE_GROWING + in :ref:`kea-messages`) + if they perceive a queue as growing too quickly. The warnings will cease once + the queue size begins to shrink. These messages are intended as a bell-weather + and seeing them sporadically during times of heavy traffic load does not + necessarily indicate a problem. If, however, they occur continually during + times of routine traffic load they likely indicate potential mismatches in + server capibilities and/or configuration and this should be investigate as the + size of the queues may eventually impair an active server's ability to respond + to clients in a timely manner. + .. _ha-sharing-lease-info: Lease Information Sharing