Veritas File System 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

The VERITAS File System
Extended mount Options
Chapter 112
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 25 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.