Example implementations relate to read operation redirect. For example, a system according in the present disclosure may include a data storage device accessible by a host. The system may include an input/output filter of an operating system of the host. The input/output filter may monitor read operations and write operations from the host to the data storage device. The input/output filter may copy a portion of the data storage device to a random-access memory (RAM) buffer within the host responsive to monitored read operations to the portion exceeding a threshold. The input/output filter may redirect a successive read operation, addressed to the portion of the data storage device, to the copy of the portion in the RAM buffer.