Oracle ASM Filter Driver (Oracle ASMFD) maintains storage file path persistence and helps to protect files from accidental overwrites.

• About Oracle ASM with Oracle ASM Filter Driver
  During Oracle Grid Infrastructure installation, you can choose to install and configure Oracle Automatic Storage Management Filter Driver (Oracle ASMFD). Oracle ASMFD helps prevent corruption in Oracle ASM disks and files within the disk group.
• Configuring Oracle ASM Filter Driver
  You can configure Oracle ASM Filter Driver (Oracle ASMFD) for device persistence during the installation of Oracle Grid Infrastructure or after Oracle Grid Infrastructure has been installed.
• About Migrating From Oracle ASMLib to Oracle ASM Filter Driver
  If ASMLIB is installed and configured for an existing Oracle ASM installation, then you must explicitly uninstall the existing ASMLIB configuration before installing and configuring Oracle ASMFD.
• Determining If Oracle ASM Filter Driver Is Configured
  The value of the AFD_STATE parameter of SYS_ASMFD_PROPERTIES specifies whether Oracle ASMFD is configured for the Oracle ASM instance.