4 Managing the Ext File System

The extended file system, or Ext, is the first file system that was written for the Linux kernel and is in common usage across many Linux distributions. Ext has evolved through several successive updates and is available as the Ext4 file system, which is largely backward compatible with previous Ext file system releases but includes many added features. Key features available in Ext4, include:

• Large file system support: Ext4 can theoretically support volumes with sizes up to 1 EiB and single files with sizes up to 16 TiB.
• Use of extents instead of block mapping: improves large file performance and reduces fragmentation.
• Recognizes fallocate for persistent preallocation of on-disk space for a file: improves performance and helps to ensure contiguous disk allocation for a file.
• Use of allocate-on-flush: helps with performance and reduces fragmentation by delaying disk space allocation until the moment that data is flushed to disk.
• Checksum functionality: ensures data integrity.

For more information, visit https://ext4.wiki.kernel.org/index.php/Main_Page.

This chapter describes tasks for administering the Ext file system in Oracle Linux 9. For an overview of local file system management, see About File System Management.