3.9.6.3 Modify an ACFS File System on Exascale

Exascale contains integrated support for Oracle Advanced Cluster File System (ACFS) on Exascale block storage using Exascale Direct Volumes (EDV).

To modify an existing Exascale-managed ACFS file system:

1. Use the ESCLI acfsctl command to deregister the file system.

   Deregistering an Exascale-managed ACFS file system dismounts and removes the Oracle Grid Infrastructure (GI) registration for the host or cluster associated with the file system. The operation also removes the mount point directory from the host or GI cluster members. However, the file system contents remain in the underlying Exascale volume.

   To deregister an Exascale-managed ACFS file system, use the acfsctl deregister command and specify the file system identifier. For example:

   @> acfsctl deregister 1:2fb06f13cddd4a8d8d636d1f794046cb

   You can use the lsacfsfilesystem command to find the identifier for each Exascale-managed ACFS file system.

   You can also bypass errors in the deregistration process by adding the --force option.

2. After deregistering the file system, you can optionally remove and re-create the EDV attachment. See Administer EDV Attachments.

   Re-creating the EDV attachment enables you to move the attachment to a different host or GI cluster, which effectively moves the file system when it is registered again.

3. Use the ESCLI acfsctl command to register the file system.

   During file system registration, you must specify:

   • The identifier of the Exascale volume that stores the file system. You can use the lsacfsfilesystem command to find the volume identifier associated with each Exascale-managed ACFS file system.

     The specified volume must have an associated EDV attachment, otherwise the operation fails.

     Furthermore, the configuration of the EDV attachment governs how the file system is implemented. If the EDV attachment is a cluster-wide attachment, the ACFS file system is mounted on every node in the GI cluster. If the EDV attachment is a node-specific attachment, the file system is mounted only on that node. In all cases, the ACFS details are registered with the GI cluster, and the file system is automatically mounted (or remounted) by Oracle Clusterware as required.

   • The mount point location where you want to mount the file system.

     The specified mount point location may differ from the location used in previous registrations.

   During file system registration, you may specify optional attributes that govern how the file system is mounted, such as mounting it in read-only mode or read-write mode. However, you cannot change fundamental settings relating to the file system, such as changing the file system encryption setting or the metadata block size.

   For example:

   @> acfsctl register 1:bbd6fb4c75e2411b9bf366fe702eabaf /mnt/acfs1 --attributes mountReadOnly=true

   In the example:

   • The volume identifier is 1:bbd6fb4c75e2411b9bf366fe702eabaf.

   • The file system mount point is /mnt/acfs1.

   • The file system is mounted in read-only mode by specifying the optional attribute setting: mountReadOnly=true.