Veritas File System 5.0 AdministratorÆs Guide, HP-UX 11i v3, First Edition, May 2008

■ minicache
■ convosync
■ ioerror
■ largefiles|nolargefiles
■ cio
Caching behavior can be altered with the mincache option, and the behavior of
O_SYNC and D_SYNC writes can be altered with the convosync option.
See the fcntl(2) manual page.
The delaylog and tmplog modes can significantly improve performance. The
improvement over log mode is typically about 15 to 20 percent with delaylog;
with tmplog, the improvement is even higher. Performance improvement varies,
depending on the operations being performed and the workload. Read/write
intensive loads should show less improvement, while file system structure
intensive loads, such as mkdir, create, and rename, may show over 100 percent
improvement. The best way to select a mode is to test representative system loads
against the logging modes and compare the performance results.
Most of the modes can be used in combination. For example, a desktop machine
might use both the blkclear and mincache=closesync modes.
See the mount_vxfs(1M) manual page.
The log mode
In log mode, all system calls other than write(2), writev(2), and pwrite(2) are
guaranteed to be persistent after the system call returns to the application.
The rename(2) system call flushes the source file to disk to guarantee the
persistence of the file data before renaming it. In both the log and delaylog
modes, the rename is also guaranteed to be persistent when the system call returns.
This benefits shell scripts and programs that try to update a file atomically by
writing the new file contents to a temporary file and then renaming it on top of
the target file.
The delaylog mode
The default logging mode is delaylog. In delaylog mode, the effects of most
system calls other than write(2), writev(2), and pwrite(2) are guaranteed to be
persistent approximately 15 to 20 seconds after the system call returns to the
application. Contrast this with the behavior of most other file systems in which
29VxFS performance: creating, mounting, and tuning file systems
Mounting a VxFS file system