To effectively reduce cache defragmentation overhead and improve cache hit radio in data-intensive workflows， a persistent client cache for distributed file system was proposed， namely DFS-Cache （Distributed File System Cache）， which was designed and implemented based on Non-Volatile Memory （NVM） and was able to ensure data persistence and crash consistency with significantly reducing cold start time. DFS-Cache was consisted of a cache defragmentation mechanism based on virtual memory remapping and a cache space management strategy based on Time-To-Live （TTL）. The former was based on the characteristic that NVM could be directly addressed by the memory controller. By dynamically modifying the mapping relationship between virtual addresses and physical addresses， zero-copy memory defragmentation was achieved. The latter was a cold-hot separated grouping management strategy that could enhance cache space management efficiency with the support of the remapping-based cache defragmentation mechanism. Experiments were conducted using real Intel Optane persistent memory devices. Compared with commercial distributed file systems MooseFS and GlusterFS， while employing standard benchmarking programs like Fio and Filebench， the proposed client cache can increase the system throughput by up to 5.73 times and 1.89 times.