Veritas File System 5.0 Administrator's Guide (September 2006)
To switch capabilities on an unmounted file system, type the following command:
# fsadm -F vxfs -o [no]largefiles special_device
You cannot change a file system to nolargefiles if it holds large files.
Seethe mount_vxfs(1M), fsadm_vxfs(1M), and mkfs_vxfs(1M) manual pages.
The cio option
The cio (Concurent I/O) option specifies the file system to be mounted for
concurrent readers and writers. Concurrent I/O is a licensed feature of VxFS. If
cio is specified, but the feature is not licensed, the mount command prints an
error message and terminates the operation without mounting the file system.
The cio option cannot be disabled through a remount. To disable the cio option,
the file system must be unmounted and mounted again without the cio option.
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, type the following:
# 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, type the following:
# 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, type the following:
39VxFS performance: creating, mounting, and tuning file systems
Choosing mount command options