Circumstances of a job failure
A job failure can result from failure of the TS7700 or of a link between TS7700 Clusters.
Failure of a TS7700
A failure of a TS7700 causes any job using that virtual device addresses to fail. The job also fails if the failed cluster is the one sourcing the data "remote TVC". To re-run the jobs, host connectivity to the virtual device addresses in another TS7700 must be enabled and an appropriate ownership takeover mode selected. If the other TS7700 has a valid copy of a virtual volume, the jobs can be retried.Failure of a grid link
If a virtual volume is being accessed in a remote cache through a 1-Gb Ethernet link and that link fails, the job that accesses that volume also fails. If the failed job is attempted again, the TS7700 uses the remaining 1-Gb Ethernet link. If both links fail, no access to any data in a remote cache is possible.Remote mount IP link failover
If a grid link fails during a remote mount the Remote Mount IP Link Failover function attempts to reestablish the connection through an alternate link. During a failover, up to three more links are attempted. If all four link connections fail, the remote mount fails, resulting in a host job failure or a synchronous mode copy break. When Synchronous Mode Copy is in use and one or both "S" sites incur a TCP/IP link failure, this intelligent failover function recovers by using an alternate link. The following restriction applies:- At least two grid connections must exist between clusters in the grid (either two or four 1 Gbps grid links or two 10 Gbps grid links).