ASM filesystem file management

 ASM  filesystem file  management

i dont' kown if should post the qeustion in storage management or scalibity rac community.

use asm filesystem , i want to kown something aboout asm management .

1. is oracle file all in Oracle-Managed Files ?

i check it  when In init.ora:
  
      DB_CREATE_FILE_DEST=+DISKG_DB

1)we create logfile use asmfilesystem file  such as 

 alter database add logfile thread 1 group 5 ('+DISKG_DB','+DISKG_FRA') size 10M;

in asm disk we find  in am filesystem such thing like

asmcmd>ls

ONLINELOG  MIRROR  FINE     NOV 09 16:00:00  Y    group_5.271.702491129             -new creately file ,this is oracle managerfile,

SQL> alter database drop   LOGFILE  group 5;