oracledba.help
SpecialTopics

File System Architectures

Overview

Before you install any software or build any database on a new system it is crucial predetermine which file system architecture you should use. This page briefly details the most common combinations. Even in cases where the application\vendor mandates which one to use it is good to know the Pros and Cons.

OMF is generally used with ASM at this point as opposed to manual file management.

TOC

Manual

Examples: 

/u01/oradata/MYDB/dbf/system.dbf
/u02/oradata/MYDB/ctl/control01.ctl
/u03/oradata/MYDB/rdo/redo01a.rdo
/u04/oradata/MYDB/arc/MYDB_0001_0000002748_934797534.arc
  • Greatest control over files.
  • Does not require any special instances or drivers.
  • Requires most administrative work.
  • Prone to lack of standardization.

Oracle Managed Files (OMF)

OMF is a service that automates naming, location, creation and deletion of database files such as control files, redo log files, data files and others. Examples: 

/u01/oradata/MYDB/DATAFILE/system.258.905963653
/u01/oradata/MYDB/TEMPFILE/temp.261.905963775
/u01/oradata/MYDB/ONLINELOG/group_4.272.905963831
/u01/oradata/MYDB/ARCHIVELOG/2017_06_02/thread_2_seq_12130.2116.945586203
  • Eases and automates most file administrative tasks.
  • Provides standardization via Oracle Optimal Flexible Architecture (OFA) compliance.
  • Less control over file and directory naming options.

ASMFD-ASM-OMF

  • ASM Filter Driver (ASMFD) is now Oracle's preferred method to manage ASM based disk resources. ASMFD deprecates ASMLib and handles the grunt work that was required to use UDev.
    • In 12.2 and later it is stable.
    • It is easy to setup and manage.
    • It prevents data corruption should something try to write to an ASMFD managed resource outside of Oracle.
  • Automatic Storage Management (ASM) aims to simplify the management of database, datafiles, control files and log files. Examples: 
+DATA/ORADB/DATAFILE/system.258.905963653
+DATA/ORADB/TEMPFILE/temp.261.905963775
+FRA/ORADB/ONLINELOG/group_4.272.905963831
+FRA/ORADB/ARCHIVELOG/2017_06_02/thread_2_seq_12130.2116.945586203
  • It can improve disk access speed and redundancy on hardware with poor performance.
  • It requires OS level driver to be used. ASMFD in this case.
  • It requires a separate instance (ex: ASM1) in addition to database instance.
  • It is functionally required for Data Guard if the Primary is using it the Standby must also.
  • It is functionally required if using RAC.

UDev-ASM-OMF

  • UDev (userspace /dev) is the native Redhat device manager for the Linux kernel.
    • It is stable.
    • It can be very tedious to setup and manage.
    • It is prone to data corruption should something write to a Udev managed resource outside of Oracle.
  • Automatic Storage Management (ASM) aims to simplify the management of database, datafiles, control files and log files. Examples: 
+DATA/ORADB/DATAFILE/system.258.905963653
+DATA/ORADB/TEMPFILE/temp.261.905963775
+FRA/ORADB/ONLINELOG/group_4.272.905963831
+FRA/ORADB/ARCHIVELOG/2017_06_02/thread_2_seq_12130.2116.945586203
  • It can improve disk access speed and redundancy on hardware with poor performance.
  • It requires OS level driver to be used (UDev in this case).
  • It requires a separate instance (ex: ASM1) in addition to database instance.
  • It is functionally required for Data Guard if the Primary is using it the Standby must also.
  • It is functionally required if using RAC.