docs/source/includes/common/scanner.rst

You can adjust how MinIO balances the scanner performance with read/write operations using either the MINIO_SCANNER_SPEED environment variable or the scanner speed <scanner.speed> configuration setting.

MinIO utilizes the scanner for bucket replication <minio-bucket-replication>, site replication <minio-site-replication-overview>, and lifecycle management <minio-lifecycle-management> tasks.

Valid values include:

fastest	Removes scanner wait on read/write latency, allowing the scanner to operate at full-speed and IOPS consumption. This setting may result in reduced read and write performance.
fast	Sets a short scanner wait time on read/write latency, allowing the scanner to operate at a higher speed and IOPS consumption. This setting may result in reduced read and write performance.
default	Sets a moderate scanner wait time on read/write latency, allowing the scanner to operate at a balanced speed and IOPS consumption. This setting seeks to maintain read and write performance while allowing ongoing scanner activity.
slow	Sets a medium scanner wait time on read/write latency, where the scanner operates at a reduced speed and IOPS consumption. This setting allows better read and write performance while reducing scanner performance. May impact scanner-dependent features, such as lifecycle management and replication.
slowest	Sets a large scanner wait time on read/write latency, where the scanner operates at a substantially lower speed and IOPS consumption. This setting prioritizes read and write operations at the potential cost of scanner operations. May impact scanner-dependent features, such as lifecycle management and replication.