Replacing a Storage Node
A simplyblock storage cluster is designed to be always up. Hence, operations such as extending a cluster or replacing a storage node are online operations and don't require a system downtime. However, there are a few things to keep in mind when replacing a storage node.
Danger
If a storage node should be migrated, Migrating a Storage Node must be followed. Removing a storage node from a simplyblock cluster without migrating it, will make the logical volumes owned by this storage node inaccessible!
Starting the new Storage Node
It is always recommended to start the new storage node before removing the old one, even if the remaining cluster has enough storage available to absorb the additional (temporary) storage requirement.
Every operation that changes the cluster topology comes with a set of migration tasks, moving data across the cluster to ensure equal usage distribution.
If a storage node failed and cannot be recovered, adding a new storage node is perfectly fine, though.
To start a new storage node, follow the storage node installation according to your chosen set-up:
Remove the old Storage Node
Danger
All volumes on this storage node, which aren't migrated before the removal will become inaccessible!
To remove the old storage node, use the sbcli-pre command line tool.
sbcli-pre storage-node remove <NODE_ID>
Wait until the operation has successfully finished. Afterward, the storage node is removed from the cluster.
This can be checked again with the sbcli-pre command line tool.
sbcli-pre storage-node list --cluster-id=<CLUSTER_ID>