From b4d9ace620e1175bf805d9926f77c10dcb0048a2 Mon Sep 17 00:00:00 2001 From: Alan Conway Date: Thu, 11 Apr 2013 17:52:47 +0000 Subject: NO-JIRA: HA doc updates to migration guide and broker book. git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1467007 13f79535-47bb-0310-9956-ffa450edef68 --- qpid/cpp/README-HA.txt | 13 +++++---- .../book/src/cpp-broker/Active-Passive-Cluster.xml | 32 ++++++++++++++-------- 2 files changed, 28 insertions(+), 17 deletions(-) (limited to 'qpid') diff --git a/qpid/cpp/README-HA.txt b/qpid/cpp/README-HA.txt index 8b1070c435..03e190a3fc 100644 --- a/qpid/cpp/README-HA.txt +++ b/qpid/cpp/README-HA.txt @@ -79,11 +79,14 @@ will be assumed broken if there is no heartbeat for twice the interval. Configuring rgmanager --------------------- -The new HA module requires an external cluster resource manager, `rgmanager` -provided by the `cman` package. `rgmanager` is responsible for stopping and -starting brokers and determining which broker is promoted to primary. It is also -responsible for detecting primary failures and promoting a new primary. See -["Configuring rgmanager as resource manager"][ha-rm-config] +The new HA module requires an external cluster resource manager. Initially it +supports `rgmanager` provided by the `cman` package. `rgmanager` is responsible +for stopping and starting brokers and determining which broker is promoted to +primary. It is also responsible for detecting primary failures and promoting a +new primary. See ["Configuring rgmanager as resource manager"][ha-rm-config] + +It is relatively easy to integrate with a new resource manager, see +["Integrating with other Cluster Resource Managers"][ha-other-rm] Broker Administration Tools --------------------------- diff --git a/qpid/doc/book/src/cpp-broker/Active-Passive-Cluster.xml b/qpid/doc/book/src/cpp-broker/Active-Passive-Cluster.xml index aef49baecf..b98e054b98 100644 --- a/qpid/doc/book/src/cpp-broker/Active-Passive-Cluster.xml +++ b/qpid/doc/book/src/cpp-broker/Active-Passive-Cluster.xml @@ -54,10 +54,16 @@ under the License. Avoiding message loss In order to avoid message loss, the primary broker delays - acknowledgment of messages received from clients until the message has - been replicated to and acknowledged by all of the back-up brokers. This means that - all acknowledged messages are safely stored on all the backup - brokers. + acknowledgment of messages received from clients until the + message has been replicated and acknowledged by all of the back-up + brokers, or has been consumed from the primary queue. + + + This ensures that all acknowledged messages are safe: they have either + been consumed or backed up to all backup brokers. Messages that are + consumed before they are replicated do not need to + be replicated. This reduces the work load when replicating a queue with + active consumers. Clients keep unacknowledged messages in a buffer @@ -82,10 +88,10 @@ under the License. - So if the primary crashes, all the acknowledged - messages will be available on the backup that takes over as the new - primary. The unacknowledged messages will be - re-sent by the clients. Thus no messages are lost. + If the primary crashes, all the acknowledged + messages will be available on the backup that takes over as the new + primary. The unacknowledged messages will be + re-sent by the clients. Thus no messages are lost. Note that this means it is possible for messages to be @@ -177,10 +183,12 @@ under the License. - Federated links from the primary will be lost - in fail over, they will not be re-connected to the new - primary. Federation links to the primary will - fail over. + Federation links to the primary will fail over + correctly. Federated links from the primary + will be lost in fail over, they will not be re-connected to the new + primary. It is possible to work around this by replacing the + qpidd-primary start up script with a script that + re-creates federation links when the primary is promoted. -- cgit v1.2.1