In general, VxFS works best if the percentage of free space in the file system is greater than 10 percent. This is because file systems with 10 percent or more of free space have less fragmentation and better extent allocation. Regular use of the df command to monitor free space is desirable. Full file systems may have an adverse effect on file system performance. Full file systems should therefore have some files removed or should be expanded.

See the fsadm_vxfs(1M) manual page.