OCFS, Features Part 2….

Here are some more features of OCFS2,

  • Advanced Security – Supports POSIX ACLs and SELinux in addition to the traditional file access permission model. Use the setfacl command to assign users specific permissions to an object. Both these security extensions require the xattr feature.
  • Metadata Checksums – Detects silent corruption in inodes and directories. This feature makes the file system compute and validate the checksums of metadata objects, such as inodes and directories, to ensure metadata integrity. It also stores an error correction code that is capable of fixing single bit errors. This feature entails an on-disk change. Enable the metaecc file system feature to activate.
  • Indexed Directories – Allows quick lookups of a directory entry in a very large directory. It also results in faster creates and unlinks, which increases overall performance. This feature entails an on-disk change. Enable the indexed-dirs file system feature to activate.
  • Quotas – Supports user and group quotas by using standard utilities such as quota, setquota, quotacheck, and quotaon. This feature involves an on-disk change. Enable the usrquota and grpquota file system features to activate.
  • JBD2 Journaling – Supports both ordered and writeback data journaling modes to provide file system consistency in the event of power failure or system crash. Journaling block device (JBD2) allows the file system to grow beyond 16 TB. Journal files in OCFS2 are stored as node local system files. Each node has exclusive access to its journal and retains a cluster lock on it for the duration of its mount.
  • In-kernel Cluster Stack (O2CB) – Includes an easy-to-configure, in-kernel cluster stack with a Distributed Lock Manager (DLM)
  • Multiple Cluster Stacks – In addition to its own in-kernel cluster stack (O2CB), enables functioning with user-space cluster stacks such as Pacemaker (pcmk), CMAN (cman), and no cluster stack (local mount)