In all logging modes, VxFS is fully POSIX compliant. The effects of the fsync(2) and fdatasync(2) system calls are guaranteed to be persistent after the calls return. The persistence guarantees for data or metadata modified by write(2), writev(2), or pwrite(2) are not affected by the logging mount options. The effects of these system calls are guaranteed to be persistent only if the O_SYNC, O_DSYNC, VX_DSYNC, or VX_DIRECT flag, as modified by the convosync= mount option, has been specified for the file descriptor.

The behavior of NFS servers on a VxFS file system is unaffected by the log and tmplog mount options, but not delaylog. In all cases except for tmplog, VxFS complies with the persistency requirements of the NFS v2 and NFS v3 standard. Unless a UNIX application has been developed specifically for the VxFS file system in log mode, it expects the persistence guarantees offered by most other file systems and experiences improved robustness when used with a VxFS file system mounted in delaylog mode. Applications that expect better persistence guarantees than that offered by most other file systems can benefit from the log, mincache=, and closesync mount options. However, most commercially available applications work well with the default VxFS mount options, including the delaylog mode.