Expanding a Storage Cluster
Simplyblock is designed as an always-on storage solution. Hence, storage cluster expansion is an online operation without a need for maintenance downtime.
However, every operation that changes the cluster topology comes with a set of migration tasks, moving data across the cluster to ensure equal usage distribution. While these migration tasks are low priority and their overhead is designed to be minimal, it is still recommended to expand the cluster at times when the storage cluster isn't under full utilization.
Info
Add storage nodes in pairs (i.e., 2, 4, 6, … nodes at a time).
Expansions with an odd number of nodes are not supported.
To add a new storage node, follow the installation steps for your chosen deployment method up to the point where nodes are added to the cluster, then continue here:
After adding the first new storage node, the cluster transitions to IN_EXPANSION and starts background rebalancing. Add the remaining node(s) required for the expansion (storage nodes must be added in pairs). Once all newly added nodes are healthy/ready, finalize the expansion:
sbctl complete-expand <CLUSTER_ID>