0 Replies Latest reply on Aug 1, 2013 11:06 PM by userTK421

    Multiple 11gR2 Clusterware installations on the same subnet using GNS




      I am hoping someone could shed some light on an issue I appear to have regarding the installation of 11gR2 Clusterware.   The main issue is that I have a host-vip.subdomain  that fails to startup on installation.  This is my 3rd cluster in my environment; the other 2 installed/configured ..fine.   This install fails because the host-vip.subdomain does not resolve with its own GNS service.


      Further investigation lead me down a path involving my other clusters.   I found in my DNS server /var/log/messages  file that the host-vip.subdomain  was trying to resolve to  host-vip.subdmain.subdomain_clust1 on IP xx.xxx.130.20.   However, this cluster's GNS service is listening on xx.xxx.130.22


      More detail on the environment:

      I currently have in production,  two  2-node clusters.   Not RAC..just 2-node linux clusters; On the production clusters, I do have a single-instance database running in a 'warm failover' configuration.   I do use SCAN to access each of the database on their respective clusters. 


      I am using GNS and DHCP (obviously) to generate the VIPs for each cluster.    Cluster1 GNS IP - xx.xxx.130.20  ; Cluster2 GNS IP xx.xxx.130.21.   Both are configured in DNS and resolve the SCAN address to each of the VIPs on that server.


      When testing SCAN access to the database, I noticed that a tnsping DB1  - which uses  SCAN-name1.subdomain1  connects fine.   Also, tnsping to DB2 using SCAN-name2.subdomain2  connects fine as well. 
      However, the weird part is that if I use each others subdomain..they still connect ...ie....tnsping DB1 using SCAN-name1.subdomain2  ...still connects to DB1.. albeit , it takes about 10x longer to get a response.   


      This has lead me to the idea that since GNS is basically a mDNS service, broadcasting on the subnet .130...could it be possible that ANY GNS service on that subnet could resolve a name lookup request for any other GNS on the same subnet , and during installation of a new server, cause a new VIP to go to the wrong GNS service  ? 


      So, my question is this :  Is there any requirement I may have missed that state multiple Clusters using GNS / SCAN  MUST BE on different subnets, as to not interfere with each other's lookup requests  ?


      Any info would be helpful


      ~ Allan