ISCAgent is automatically installed with Cache, runs as a service and can be configured to start with the system. This is fine – but the complication comes when this is on VCS clusters with Mirroring on. When installing a Single Instance of Cache in a Cluster, point number 2. Says “Create a link from /usr/local/etc/cachesys to the shared disk. This forces the Caché registry and all supporting files to be stored on the shared disk resource you have configured as part of the service group.”
So on the second passive node – this statement makes ISCAgent startup with the system, nor manually starting it impossible as all the binaries will be on the primary node shared disk. Up until Cache fail-over, then you are able to start it up when binaries are now local. So the issue is that in a disaster failover scenario Cache automatically starts on the second node without ISCAgent and throws all sorts of errors, locks DB and all connection with sign-on inhibited – up until someone manually connects and start it up. The ideal scenario I am looking at is a mechanism to also automatically start ISCAgent during the failover to the secondary node.
What suggestions are out there to make ISCAgent start up automatically on second node when the cluster fail over in a VCS configuration like this?
SPOOLER functionality is support in Cache 16? Previously we are using cache 5,Now we upgraded cache(cache 16). Is any changes required in SPOOLER set-up (Cache 16)?
One of the great availability and scaling features of Caché is Enterprise Cache Protocol (ECP). With consideration during application development distributed processing using ECP allows a scale out architecture for Caché applications. Application processing can scale to very high rates from a single application server to the processing power of up to 255 application servers with no application changes.
I saw someone recently refer to ECP as magic. It certainly seems so, and there is a lot of very clever engineering to make it work. But the following sequence of diagrams is a simple view of how data is retrieved and used across a distributed architecture.
