HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide

100 Chapter5
Performance and Tuning
Choosing Mount Options
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.