Linux disk I/O diagram

Linux Disk I/O subsystem diagram

This diagram represents Linux disk I/O subsystem components and the corresponding commands on each layer.

Linux disk I/O diagram consists from the:

• Application layer.
• VFS (Virtual Filesystem):
  • Direct I/O or
  • Buffer+Page Cache 
• Optional block layer.
• Filesystem Layer.
• Generic block layer.
• Disk scheduler layer:
  • BLK-Mq or
  • Clasic I/O scheduler (noop, anticipatory, deadline, cfq, ...)
• Block device driver layer.
• Device driver.
• Hardware:
  • RAID controller or
  • Disk controller
• Hard disk drives (HDD, SSD, NVMe, ...).