06-08-2015 01:01 AM
hi,
i understand that a gco is a virtual(global) cluster formed from 2 vcs clusters each one in a separate site.the heartbeat between nodes from the sites goes over the wan?the gab traffic that updates all the nodes between the 2 sites,goes over this wan between sites?
Solved! Go to Solution.
06-08-2015 01:59 AM
Hi,
Yes, the heartbeat between two sites goes via ICMP traffic over WAN. GCO uses resource called WAC to form this heartbeat.
If you look at GAB output, GAB will not form a membership with remote site, GAB will have local membership with local nodes. You can identify remote nodes using "hastatus -sum" command which will show status of remote site
You can query status of heartbeat using "hahb" command ..
https://sort.symantec.com/public/documents/vcs/6.0/solaris/productguides/html/vcs_admin/ch18s02s06.htm
G
06-08-2015 02:35 AM
Hi,
Your understanding on GCO is right. Global Cluster Option(popularly known as GCO) is a global cluster formed from atleast 2 VCS clusters, each one in a separate site. This clusters are NOT geographically co-located(usually, separated by more than 80 kilometers).
HB between clusters: There is ICMP based heartbeat between clusters, which goes over the WAN. You can check remote clusters HB connectivity using “hahb” command.
E.g. In 2 cluster GCO(Pune and Mumbai), “hahb –state” executed from Pune gives connectivity between it and Mumbai cluster.
# haclus -state
#Cluster Attribute Value
Pune ClusState RUNNING
Mumbai ClusState RUNNING
# hahb -state
#HB Attribute Scope Value
Icmp State Mumbai ALIVE
Message/State exchange between cluster: Wide-Area Connector(WAC) process runs on one of the node in each cluster. It is used for message/state exchange between clusters. This process listens for connection from remote clusters on port number 14155(default wac port). It is configured in ClusterService group.
GAB: GAB maintains membership between local nodes of a cluster. It never spans across clusters.
Thanks & Regards,
Sunil Y
06-08-2015 01:59 AM
Hi,
Yes, the heartbeat between two sites goes via ICMP traffic over WAN. GCO uses resource called WAC to form this heartbeat.
If you look at GAB output, GAB will not form a membership with remote site, GAB will have local membership with local nodes. You can identify remote nodes using "hastatus -sum" command which will show status of remote site
You can query status of heartbeat using "hahb" command ..
https://sort.symantec.com/public/documents/vcs/6.0/solaris/productguides/html/vcs_admin/ch18s02s06.htm
G
06-08-2015 02:13 AM
These posts may help you to gain further understanding ..
https://www-secure.symantec.com/connect/forums/vcs-global-cluster-configuration
https://www-secure.symantec.com/connect/forums/gco-configuration-between-2-nodes-cluster-and-1node-cluster
G
06-08-2015 02:35 AM
Hi,
Your understanding on GCO is right. Global Cluster Option(popularly known as GCO) is a global cluster formed from atleast 2 VCS clusters, each one in a separate site. This clusters are NOT geographically co-located(usually, separated by more than 80 kilometers).
HB between clusters: There is ICMP based heartbeat between clusters, which goes over the WAN. You can check remote clusters HB connectivity using “hahb” command.
E.g. In 2 cluster GCO(Pune and Mumbai), “hahb –state” executed from Pune gives connectivity between it and Mumbai cluster.
# haclus -state
#Cluster Attribute Value
Pune ClusState RUNNING
Mumbai ClusState RUNNING
# hahb -state
#HB Attribute Scope Value
Icmp State Mumbai ALIVE
Message/State exchange between cluster: Wide-Area Connector(WAC) process runs on one of the node in each cluster. It is used for message/state exchange between clusters. This process listens for connection from remote clusters on port number 14155(default wac port). It is configured in ClusterService group.
GAB: GAB maintains membership between local nodes of a cluster. It never spans across clusters.
Thanks & Regards,
Sunil Y
06-08-2015 07:22 AM
Just to clarify, LLt/GAB is very "chatty" so will communicate all state and config changes down to resource level between nodes in a local cluster. For GCO, there is no GAB between sites and instead there is a "wac" (wide area connector) resource in the ClusterService group which communicates with the wac resource in the other globally connected clusters (as Sunil says above). The wac resource is a lot less chatty and only communicates state of group and cluster (not resources).
The wac resource communicates on the address specified by the "ClusterAddress" cluster attribute and you also have a global heartbeat which is normally the same IP, but it can be a different network if you have one and the heartbeat just transmits AYA (are you alive).
Mike