VERITAS File System 4.1 Administrator's Guide

VxFS Performance: Creating, Mounting, and Tuning File Systems
Choosing mount Command Options
Chapter 250
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.
Example 1 - Desktop File System
# 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, once an application is exited and its files are closed, no data will be lost even if the
system is immediately turned off.
Example 2 - Temporary File System or Restoring 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 specially (which could result in a file that
contains garbage if the system crashes at the wrong time). Any file written 30 seconds or so
before a crash may contain garbage or be missing if this mount combination is in effect.
However, such a file system will do significantly less disk writes than a log file system, and
should have significantly better performance, depending on the application.
Example 3 - Data Synchronous Writes
# mount -F vxfs -o log,convosync=dsync /dev/dsk/c1t3d0 /mnt
This combination would be used to improve the performance of applications that perform
O_SYNC writes, but only require data synchronous write semantics. Their performance can be
significantly improved if the file system is mounted using convosync=dsync without any loss
of data integrity.