Hello,
I am using Ganglia for some of the clusters in our calculation center
and I found out that most of the config problems are related to network
tuning.
Here is the last one, for information:
Ganglia 2.5.7
One cluster made of 32 HP nodes with 2 x AMD 64 bits Opteron 2.2 GHz
Cisco Catalyst 6500, 1 VLAN only on cluster side
Problem: XML stream is not consistent and only one node out of 32 is
shown as up and running, others are visible only from time to time, and
show partial metrics.
Solution:
Per default Catalyst boxes 65xx come with these igmp options:
IGMP is disabled on interface
Multicast routing is disabled on interface
Multicast TTL threshold is 0
No multicast groups joined by this system
IGMP snooping is globally enabled
IGMP snooping is enabled on this interface
IGMP snooping fast-leave is disabled and querier is disabled
IGMP snooping explicit-tracking is enabled on this interface
What is missing is the IGMP querier to support IGMP snooping within a
VLAN where PIM and IGMP are not configured because the multicast traffic
does not need to be routed.
If you enable the igmp querier (simple ¨ip igmp snooping querier¨
command in config mode), everything works just fine.
Regards,
Jeremy Ory
System Engineer and Network Architect
Computing Department
European Gravitational Observatory (EGO) - Cascina (Pisa), Italy
Email [EMAIL PROTECTED]
