From c4eab456ab9f634cd7fa0ce36749432d36d03a2b Mon Sep 17 00:00:00 2001 From: Martin Schwenke Date: Sat, 10 Dec 2016 14:50:21 +1100 Subject: [PATCH] ctdb-docs: Document that tunables should be set the same on all nodes Signed-off-by: Martin Schwenke Reviewed-by: Amitay Isaacs --- ctdb/doc/ctdb-tunables.7.xml | 28 ++++++++++++++++++---------- 1 file changed, 18 insertions(+), 10 deletions(-) diff --git a/ctdb/doc/ctdb-tunables.7.xml b/ctdb/doc/ctdb-tunables.7.xml index 8143a45a795..1e263dac9a4 100644 --- a/ctdb/doc/ctdb-tunables.7.xml +++ b/ctdb/doc/ctdb-tunables.7.xml @@ -29,6 +29,14 @@ getvar commands for more details. + + Unless otherwise stated, tunables should be set to the same + value on all nodes. Setting tunables to different values across + nodes may produce unexpected results. Future releases may set + (some or most) tunables globally across the cluster but doing so + is currently a manual process. + + The tunable variables are listed alphabetically. @@ -177,13 +185,12 @@ EnableBans Default: 1 - This parameter allows ctdb to ban a node if the node is misbehaving. + This parameter allows ctdb to ban a node if the node is misbehaving. When set to 0, this disables banning completely in the cluster and thus nodes can not get banned, even it they break. Don't - set to 0 unless you know what you are doing. You should set - this to the same value on all nodes to avoid unexpected behaviour. + set to 0 unless you know what you are doing. @@ -362,10 +369,9 @@ If no nodes are HEALTHY then by default ctdb will happily host public IPs on disabled (unhealthy or administratively disabled) nodes. This can cause problems, for example if the underlying - cluster filesystem is not mounted. When set to 1 on a node and - that node is disabled, any IPs hosted by this node will be - released and the node will not takeover any IPs until it is no - longer disabled. + cluster filesystem is not mounted. When set to 1 and a node + is disabled, any IPs hosted by this node will be released and + the node will not takeover any IPs until it is no longer disabled. @@ -374,9 +380,11 @@ Default: 0 When set to 1, ctdb will not allow IP addresses to be failed - over onto this node. Any IP addresses that the node currently - hosts will remain on the node but no new IP addresses can be - failed over to the node. + over to other nodes. Any IP addresses already hosted on + healthy nodes will remain. Usually IP addresses hosted on + unhealthy nodes will also remain, if NoIPHostOnAllDisabled is + 0. However, if NoIPHostOnAllDisabled is 1 then IP addresses + will be released by unhealthy nodes and will become un-hosted. -- 2.34.1