Can StorageGRID nodes be added to a GRID with different drive capacity nodes
Applies to
StorageGRID
Answer
Yes. You can add the same appliance type with higher capacity.
In a situation where an SG5712 with 22TB drives is added to a GRID with one site, 3 - SG5712 nodes with 8TB, and an ILM using a 2+1 EC; and, an EC rebalance is performed, all nodes will now have approximately the same amount of erasure-code data. However, the Used (%) for the larger node will be less than the Used (%) for the smaller nodes.
Because the nodes with lesser capacity will eventually become full before the nodes with bigger capacity, we need to make sure enough nodes are added to avoid an ILM placement unachievable situation when the nodes with lesser capacity become full. The amount of nodes to be added to a GRID when the nodes are the same model but with different drive capacity will depend on the ILM policy in place.
For the example provided, it is recommended to add three or more new Storage Nodes. StorageGRID requires three Storage Nodes for 2+1 erasure coding so that it can place the two data fragments and the one parity fragment on different nodes.
Once the three Storage Nodes are added, if the Storage nodes with less drive capacity become full, objects can continue to be ingested into the 2+1 erasure coding scheme on the new nodes with higher capacity.