A computer-implemented method for caching content in a cache memory device is disclosed. The method starts with receiving, at a cache manager, one or more data chunks to be cached in a cache memory device, where the one or more data chunks are retrieved from a persistent storage disk of a storage system in response to a read request of a region of a file. Then the one or more data chunks of a file extent is compressed using a predetermined compression algorithm, and the file extent is packed into a write-evict unit (WEU) maintained in a random-access memory (RAM) that has been open to store a plurality of file extents. In response to determining that the WEU is full, the cache manager writes the WEU from the RAM into the cache memory device.