Filesystem Name and Attribute Caching

This section provides a simplified view of how the kernel algorithms work. Some of the details are skipped, as the intent is to understand the measurements provided by sar. This topic has already been covered in some detail in “File Access Caching with Local Disk” on page 307.

Vnodes, Inodes, and Rnodes

Unix traditionally uses inodes to hold the information required to access files, such as the size, owner, permissions, modification date and the location of the data blocks for the file. SunOS 4, SVR4, and Solaris 2 all use a higher-level abstraction called a virtual node, or vnode. This scheme allows all filesystem types to be implemented in the same way since the kernel works in terms of vnodes and each ...

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