Home > Storage > PowerScale (Isilon) > Product Documentation > Storage (general) > Dell PowerScale: Considerations and Best Practices for Large Clusters > Cluster capacity considerations
When a large cluster, or any of its nodepools, becomes more than 95% full, OneFS can experience slower performance and possible workflow interruptions in degraded mode and high-transaction or write-speed-critical operations. Furthermore, when a large cluster approaches full capacity (over 98% full), the following issues can occur:
To ensure that a cluster or its constituent pools do not run out of space:
When deciding to add new nodes to an existing large cluster or pool, contact your sales team to order the nodes well in advance of the cluster or pool running short on space. The recommendation is to start planning for additional capacity when the cluster or pool reaches 75% full. This will allow sufficient time to receive and install the new hardware, while still maintaining sufficient free space.
The following table presents a suggested timeline for large cluster capacity planning.
Used capacity | Action |
75% | Plan additional node purchases. |
80% | Receive delivery of the new hardware. |
85% | Rack and install the new node(s). |