# Compaction takes lots of memory and CPU

ScyllaDB runs compaction periodically as a background process. While running compaction is important, there are situations when
compaction takes too much CPU.
As a result, compaction impacts the overall system performance.

If this is the case, you can do one of the following:

* Statically limit the compaction shares with the `compaction_static_shares` option by setting a value between 50 and 1000:
  > * In the `scylla.yml` configuration file: `compaction_static_shares: 100`
  > * In the command line when starting ScyllaDB: `--compaction-static-shares 100`

  You may start by setting the value `100`. If read latency is impacted, which indicates that compaction is overly slowed down,
  you can increase the value to reach the balance between the system performance and read latency.
* Enforce `min_threshold` by setting `compaction_enforce_min_threshold: true` in the `scylla.yml` configuration file ([default is False](https://docs.scylladb.com/manual/stable/reference/configuration-parameters.html#confval-compaction_enforce_min_threshold)).
  As a result, ScyllaDB will compact only the buckets that contain the number of SSTables specified with `min_threshold`
  or more. See [STCS options](https://docs.scylladb.com/getting-started/compaction/#stcs-options) for details.