Improved UFS Direct I/O Concurrency

The performance of direct I/O is used by database applications to access unbuffered file-system data. Direct I/O improvements allow concurrent read access and write access to regular UFS files. Previously, an operation that updated file data would lock out all other read or write accesses until the update operation was completed.

See the System Administration Guide: Basic Administration and the man page, mount_ufs(1M), for more information.