Add a troubleshooting guide. I'm sure other folks have some good stuff to put in here. These are just the ones I know about :) Signed-off-by: Steven Dake <sdake@xxxxxxxxxx> --- man/corosync.conf.5 | 39 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/man/corosync.conf.5 b/man/corosync.conf.5 index 8e774c1..881accb 100644 --- a/man/corosync.conf.5 +++ b/man/corosync.conf.5 @@ -678,6 +678,45 @@ Native means one of shm or socket, depending on what is supported by OS. On syst with support for both, SHM is selected. SHM is generally faster, but need to allocate ring buffer file in /dev/shm. +.SH "TROUBLESHOOTING" +.TP +Occassionally Corosync will not work with the default network. Here are some +common tips that people have used to find a working Corosync. + +.TP +Disable the firewall. The firewall could block Corosync packets from reaching +the network. + +.TP +Force IGMP v2. Some modern switches do not support the kernel IGMP v3 + protocol. As a result, they will not properly register the cluster. To do +this, simply run the command + +.BR sysctl -w net.ipv4.conf.all.force_igmp_version=2 + +.TP +If on a routed network, set a larger TTL. The TTL tells the routers how long +to let the packet multicast before dropping it permanently. The default ttl +is set to 1, which means the packet will drop after its first hop. This will +not work well on a routed network. + +.TP +I use a VLAN and Corosync doesn't work. If you're using a VLAN, VLAN's shave +the packet size available for Corosync to use in some cases. Corosync does not +automatically adjust to the VLAN packet size. Set netmtu appropriately when +using a VLAN. + +.TP +If all else fails, use UDPU. The authors implemented UDPU to solve the various +problems with multicast that plague modern switch implementations. The UDPU +protocol was initially believed to be much slower but the reality after +implementation is that it doesn't make much difference. + +Even with UDPU you would be hard pressed to find a faster group messaging +system than Corosync. The only downside of UDPU is it results in much more +packet copying across the network. + + .SH "FILES" .TP /etc/corosync/corosync.conf -- 2.1.0 _______________________________________________ discuss mailing list discuss@xxxxxxxxxxxx http://lists.corosync.org/mailman/listinfo/discuss
