Limitations with delayed allocation for extending writes feature

Last published : Sep 18, 2026
The following limitations apply to the delayed allocation for extending writes feature:
  • In the cases where the file data must be written to disk immediately, delayed allocation is disabled on that file. Examples of such cases include Direct I/O, concurrent I/O, FDD/ODM access, and synchronous I/O.
  • Delayed allocation is not supported on memory mapped files.
  • Delayed allocation is not supported with BSD quotas. When BSD quotas are enabled on a file system, delayed allocation is turned off automatically for that file system.
  • Delayed allocation is not supported for shared mounts in a cluster file system.