Oracle ACFS Configuring ACFS File System for Mounting

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In this article, we will discuss how to create an ACFS (Automatic Storage Management Cluster File System) file system and mount it as a normal file system. ACFS is a file system specifically designed for Oracle ASM (Automatic Storage Management) and allows users to store and access files directly from the database. This is a highly requested topic, so let’s dive into it and explore the steps.

Configuring ACFS File System

To begin, let’s understand the setup we have for this demonstration. We have a two-node Oracle RAC (Real Application Cluster) configuration consisting of Server A and Server B. Server A runs ASM1, while Server B runs ASM2. Additionally, we have two Oracle instances, “orcl instance 1” on Node 1 and “orcl instance 2” on Node 2. These instances commonly access a disk group, which is a collection of multiple disks.

The disk group is made up of multiple disks, such as disk 1, disk 2, and disk 3. These disks combine to form the data disk group. Similarly, disk 4, disk 5, and disk 6 form the recovery disk group. We have assumed that each disk is 100 GB in size, making the data disk group approximately 300 GB and the recovery disk group approximately 400 GB. However, our database only utilizes 50 GB of the data disk group, leaving a significant amount of unused space.

The Need for ACFS File System

So, why do we need to create an ACFS file system? The unused space in the data disk group can be considered a waste. Instead of letting it remain unused, we can utilize this space for other purposes, such as storing backup files, log files, or trace files. By creating an ACFS file system, we can mount this disk group as a normal file system and perform regular file operations like copying, moving, renaming, and deleting.

Preparing the Lab Environment

Let’s move on to configuring the ACFS file system in our lab environment. First, let’s verify the installation of the necessary ASM and ACFS modules. By running the command lsmod | grep ora, we can ensure that both the ACFS and ADVM (ASM Dynamic Volume Manager) modules are installed on both nodes.

Next, we need to connect to the ASM instance on Node 1 using sqlplus / as sysdba and check the status of our disk groups using the command show diskgroup. Here, we can see that we have a disk group called “safs” with a capacity of 40 GB. Additionally, we have the data disk group and the recovery disk group, with sizes of 60 GB and 40 GB, respectively.

Creating an ACFS Volume

Now, let’s proceed with creating an ACFS volume. We will allocate 10 GB from the “safs” disk group to create an ACFS volume called “safs_test1”. To execute this, we will use the command asmcmd followed by volcreate. By running the command asmcmd volinfo -G safs -V safs_test1, we can verify the creation and details of the newly created volume.

After creating the volume, we need to start the ACFS resource using the command crsctl start resource ora.acfs.safs_test1.advm. This will ensure that the ACFS volume is available and online. By running the command crsctl status resource ora.acfs.safs_test1.advm, we can confirm that the ACFS volume is indeed online and accessible on both nodes.

Formatting the ACFS File System

Now that we have the ACFS volume, we can proceed to format it as an ACFS file system. We will use the command mkfs -t acfs /dev/asm/safs_test1-XXX (replace XXX with the volume device number). This command will format the volume as an ACFS file system. After successful formatting, we can mount the ACFS file system using the command mount -t acfs /dev/asm/safs_test1-XXX /mnt/safs_test1 (replace XXX with the volume device number and “/mnt/safs_test1” with the desired mount point).

Verifying the ACFS File System

To ensure that the ACFS file system is mounted correctly, we can run the command df -h and check if the mount point (“/mnt/safs_test1”) is listed. Additionally, we can perform a quick verification by creating a file in the ACFS file system and then listing the contents of the file system to confirm the successful creation.


In conclusion, configuring an ACFS file system allows us to allocate the unused space in an ASM disk group and utilize it as a normal file system. By following the steps outlined in this article, you can successfully create an ACFS file system, mount it, and perform regular file operations. This not only maximizes the utilization of storage but also simplifies file management within the database environment.

Remember, ACFS is an essential feature of Oracle ASM that allows for flexible and efficient storage management. So, make the most out of it by effectively configuring ACFS file systems for your database needs.