Resource Usage and Management

Usage

• threads
  • configurable number of threads
    • reading from kernel
    • processing messages from kernel
    • readdir concurrency
• memory
  • 1MB+ pre reader thread + inflight processing for messages depending on fuse-msg-size
  • buffers allocated temporarily for reading directories
  • FUSE nodes
  • never-forget-nodes=true nodes

Management

• To limit the risk of the Linux kernel's OOM Killer targeting mergerfs it sets its oom_score_adj value to -990.
• mergerfs increases its available file descriptor and file size limit.
• mergerfs sets its scheduling priority (nice value) to -10 (by default), raising its CPU scheduling priority above the default of 0.
• The readahead values of mergerfs itself and managed filesystems can be modified.