Administering ASM Cluster File Systems
Oracle
Automatic Storage Management Cluster File System (Oracle ACFS) is a
multi-platform, scalable file system, and storage management technology
that extends Oracle Automatic Storage Management (Oracle ASM)
functionality to support customer files maintained outside of Oracle
Database. Oracle ACFS supports many database and application files,
including executables, database trace files, database alert logs,
application reports, BFILEs, and configuration files. Other supported
files are video, audio, text, images, engineering drawings, and other
general-purpose application file data.
The ASM feature of Oracle database has been extended in Oracle Grid Infrastructure 11g Release 2 to include support for a general-purpose cluster file system, the ASM Cluster File System (ACFS). To understand the operation of this feature, some terminology needs to be defined and explained. At the operating system (OS) level, the ASM instance provides the disk group, which is a logical container for physical disk space. The disk group can hold ASM database files and ASM dynamic volume files. The ASM Dynamic Volume Manager (ADVM) presents the volume device file to the operating system as a block device. The mkfs utility can be used to create an ASM file system in the volume device file.
Four OS kernel modules loaded in the OS provide the data service. On Linux, they are: oracleasm, the ASM module; oracleadvm, the ASM dynamic volume manager module; oracleoks, the kernel services module; and oracleacfs, the ASM file system module. These modules provide the ASM Cluster File System, ACFS snapshots, the ADVM, and cluster services. The ASM volumes are presented to the OS as a device file at /dev/asm/<volume name>-<number>.
The volume device file appears as another ASM file to the ASM Instance and asmcmd utility. The ASM layers are transparent to the OS file system commands. Only the files and directories created in ACFS and the ACFS snapshots are visible to the OS file system commands. Other file system types such as ext3 and NTFS may be created in an ADMV volume using the mkfs command on Linux and advmutil commands on Windows.
The ASM feature of Oracle database has been extended in Oracle Grid Infrastructure 11g Release 2 to include support for a general-purpose cluster file system, the ASM Cluster File System (ACFS). To understand the operation of this feature, some terminology needs to be defined and explained. At the operating system (OS) level, the ASM instance provides the disk group, which is a logical container for physical disk space. The disk group can hold ASM database files and ASM dynamic volume files. The ASM Dynamic Volume Manager (ADVM) presents the volume device file to the operating system as a block device. The mkfs utility can be used to create an ASM file system in the volume device file.
Four OS kernel modules loaded in the OS provide the data service. On Linux, they are: oracleasm, the ASM module; oracleadvm, the ASM dynamic volume manager module; oracleoks, the kernel services module; and oracleacfs, the ASM file system module. These modules provide the ASM Cluster File System, ACFS snapshots, the ADVM, and cluster services. The ASM volumes are presented to the OS as a device file at /dev/asm/<volume name>-<number>.
The volume device file appears as another ASM file to the ASM Instance and asmcmd utility. The ASM layers are transparent to the OS file system commands. Only the files and directories created in ACFS and the ACFS snapshots are visible to the OS file system commands. Other file system types such as ext3 and NTFS may be created in an ADMV volume using the mkfs command on Linux and advmutil commands on Windows.
Objectives
- Administer ASM Dynamic Volume Manager
- Manage ASM volumes
- Implement ASM Cluster File System
- Manage ASM Cluster File System (ACFS)
- Use ACFS Snapshots
- Use command-line tools to
manage ACFS
Topics
- ACFS and ADVM Architecture Overview
- ASM Cluster File System
- ADVM Processes
- Striping Inside the Volume
- Creating an ACFS Volume
- Extending ASMCMD for Dynamic Volumes
- ACFS Snapshots
- ACFS Replication
Refer the links below:
Introduction to Oracle ACFS
Oracle ACFS Advanced Topics
Administrating ACFS
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