Distributed filesystems

What is a filesystem?

File systems determine how data is stored and retrieved. A file system keeps track of the following data items:

  • Files, where the data we want to store are.
  • Directories, which group files together
  • Metadata, such as file length, permissions and file types

The primary job of the filesystem is to make sure that the data is always accessible and in tackt. To maintain consistency, most modern filesystems use a log (remember databases!).

Common filesystems are EXT4, NTFS, APFS and ZFS

reading from a filesystem

Read system call routing in FreeBSD

reading from a file, block layer