VERITAS File System 4.1 Administrator's Guide

The VERITAS File System
Extended mount Options
Chapter 124
Extended mount Options
The VxFS file system supports extended mount options to specify:
• Enhanced data integrity modes
• Enhanced performance modes
• Temporary file system modes
• Improved synchronous writes
• Large file sizes
See “VxFS Performance: Creating, Mounting, and Tuning File Systems” on page 37 and the
mount_vxfs (1M) manual page for details on the VxFS mount options.
Enhanced Data Integrity Modes
NOTE See the mkfs_vxfs(1M) and the fsadm_vxfs(1M) manual pages for more
information on intent log size.
Most file systems are “buffered” in that resources are allocated to files and data is written
asynchronously to files. In general, the buffering schemes provide better performance without
compromising data integrity.
If a system failure occurs during space allocation for a file, uninitialized data or data from
another file may appear in the extended file after reboot. Data written shortly before the
system failure may also be lost.
Using blkclear Option for Data Integrity
In environments where performance is more important than absolute data integrity, the
preceding situation is not of great concern. However, VxFS supports environments that
emphasize data integrity by providing the mount -o blkclear option that ensures
uninitialized data does not appear in a file.
Using closesync Option for Data Integrity
VxFS provides the mount -o mincache=closesync option, which is useful in desktop
environments with users who are likely to shut off the power on machines without halting
them first. In closesync mode, only files that are written during the system crash or
shutdown can lose data. Any changes to a file are flushed to disk when the file is closed.