--- title: Build garbage collection description: Learn about garbage collection in the BuildKit daemon keywords: build, buildx, buildkit, garbage collection, prune, gc aliases: - /build/building/cache/garbage-collection/ --- While [`docker builder prune`](/reference/cli/docker/builder/prune.md) or [`docker buildx prune`](/reference/cli/docker/buildx/prune.md) commands run at once, garbage collection runs periodically and follows an ordered list of prune policies. Garbage collection runs in the BuildKit daemon. The daemon clears the build cache when the cache size becomes too big, or when the cache age expires. The following sections describe how you can configure both the size and age parameters by defining garbage collection policies. ## Configuration Depending on the [driver](../builders/drivers/_index.md) used by your builder instance, the garbage collection will use a different configuration file. If you're using the [`docker` driver](../builders/drivers/docker.md), garbage collection can be configured in the [Docker Daemon configuration](/reference/cli/dockerd.md#daemon-configuration-file). file: ```json { "builder": { "gc": { "enabled": true, "defaultKeepStorage": "10GB", "policy": [ { "keepStorage": "10GB", "filter": ["unused-for=2200h"] }, { "keepStorage": "50GB", "filter": ["unused-for=3300h"] }, { "keepStorage": "100GB", "all": true } ] } } } ``` For other drivers, garbage collection can be configured using the [BuildKit configuration](../buildkit/toml-configuration.md) file: ```toml [worker.oci] gc = true gckeepstorage = 10000 [[worker.oci.gcpolicy]] keepBytes = 512000000 keepDuration = 172800 filters = [ "type==source.local", "type==exec.cachemount", "type==source.git.checkout"] [[worker.oci.gcpolicy]] all = true keepBytes = 1024000000 ``` ## Default policies Default garbage collection policies apply to all builders if not set: ```text GC Policy rule#0: All: false Filters: type==source.local,type==exec.cachemount,type==source.git.checkout Keep Duration: 48h0m0s Keep Bytes: 512MB GC Policy rule#1: All: false Keep Duration: 1440h0m0s Keep Bytes: 26GB GC Policy rule#2: All: false Keep Bytes: 26GB GC Policy rule#3: All: true Keep Bytes: 26GB ``` - `rule#0`: if build cache uses more than 512MB delete the most easily reproducible data after it has not been used for 2 days. - `rule#1`: remove any data not used for 60 days. - `rule#2`: keep the unshared build cache under cap. - `rule#3`: if previous policies were insufficient start deleting internal data to keep build cache under cap. > [!NOTE] > > `Keep Bytes` defaults to 10% of the size of the disk. If the disk size cannot > be determined, it uses 2GB as a fallback.