- Multisite-Cluster always syncs synchronously.
- Gateway connection handles the control traffic
- Windows systems are connected to the node that holds the data. This because of the DSM driver.
- For VMware this feature is available for SanIQ >= 12.5 with necessary patch installed for vSphere 5.5 and later.
- Advantage of Multisite Cluster is that Gateway is always on local site.
- To be able to failover after a complete site failure at least nRAID-10 is necessary.
- Cluster Swap
- Create a new cluster using new nodes
- Present the new VIP to existing hosts
- Start Cluster Swap in CMC
- P4000 replicates data from existing cluster to new cluster
- after completing, traffic from hosts just accessing new cluster
- Adding new nodes to existing cluster
- Add new node to cluster, wait to complete re-striping
- Remove old node from cluster
- repeat until ever node is replaced
- When adding a new node, it is optimally the same as already used nodes in the cluster. Otherwise the used capacity of the new node will just be as the capacity of existing nodes.
- Queue size
- Acceptable queue size of disk is 2.
- Acceptable queue size of node = (number disks) * 2
- Acceptable queue size of cluster = (number disks) * (number of nodes) * 2
- When there is a high write rate in cluster presenting storage to Oracle database, check archiving protocol data when there is a very high write density.