Veritas™ File System 5.0.1 Administrator's Guide

The mntunlock option of the vxumount command reverses the mntlock option if

you previously locked the file system.

Combining mount command options

Although mount options can be combined arbitrarily, some combinations do not

make sense. The following examples provide some common and reasonable mount

option combinations.

To mount a desktop file system using options:

# mount -F vxfs -o log,mincache=closesync /dev/dsk/c1t3d0 /mnt

This guarantees that when a file is closed, its data is synchronized to disk and

cannot be lost. Thus, after an application has exited and its files are closed, no

data is lost even if the system is immediately turned off.

To mount a temporary file system or to restore from backup:

# mount -F vxfs -o tmplog,convosync=delay,mincache=tmpcache \

/dev/dsk/c1t3d0 /mnt

This combination might be used for a temporary file system where performance

is more important than absolute data integrity. Any O_SYNC writes are performed

as delayed writes and delayed extending writes are not handled. This could result

in a file that contains corrupted data if the system crashes. Any file written 30

seconds or so before a crash may contain corrupted data or be missing if this

mount combination is in effect. However, such a file system does significantly

less disk writes than a log file system, and should have significantly better

performance, depending on the application.

To mount a file system for synchronous writes:

# mount -F vxfs -o log,convosync=dsync /dev/dsk/c1t3d0 /mnt

This combination can be used to improve the performance of applications that

perform O_SYNC writes, but only require data synchronous write semantics.

Performance can be significantly improved if the file system is mounted using

convosync=dsync without any loss of data integrity.

Tuning the VxFS file system

This section describes the following kernel tunable parameters in VxFS:

■ Tuning inode table size

■ [Unresolved xref]

VxFS performance: creating, mounting, and tuning file systems

Tuning the VxFS file system