Single indexer node solutions run the most efficiently. There is no need for duplicated storage. Multi indexer node clusters require additional storage but provide for higher availability and aggregate performance.

## Single node storage

Calculate the storage required for a single node storage configuration as follows:

For example, given the following parameters:

- 100 GB per day ingest rate
- 0.5 compression rate
- Two different retention rates:

- 30 Days Hot/Warm retention
- 180 Days Cold retention

Applying the formula above yields the following results:

## Cluster storage

A Splunk cluster has an additional factor to consider when sizing the needed storage. You choose the replication factor, or number of copies of data. N replicas require N * the storage that is listed above and allow N-1 nodes to fail before losing your data. Installing a cluster with a replication factor of 2 (original + 1 replica) requires twice the storage as calculated above.