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Chapter 1 Introduction to Gluster Storage for Oracle Linux

Gluster is a scalable, distributed file system that aggregates disk storage resources from multiple servers into a single global namespace. This chapter provides introductory information about Gluster Storage for Oracle Linux.

Note

In this document, the terms master and slave that were previously used to describe redundant storage architecture have been replaced by the less divisive terms primary and secondary.

1.1 About Gluster Storage for Oracle Linux

Release 8 of Gluster Storage for Oracle Linux is based on the stable release of the upstream Gluster 8 release and is available for both Oracle Linux 7 and Oracle Linux 8.

Differences between Oracle's version of the software and upstream releases are limited to Oracle specific fixes and patches for specific bugs.

For comprehensive Gluster documentation, see https://docs.gluster.org/en/latest/.

For more information about Gluster, go to https://www.gluster.org/.

1.2 Notable Updates and New Features

This section contains information on the notable updates and new features in the major releases of Gluster Storage for Oracle Linux.

1.2.1 Notable Updates and New Features in Release 8

Some highlighted features in GlusterFS 8 are:

Support for healing data in 1 Mb blocks for better performance.
IPv6 packets are now supported by the glustereventsd daemon.
fsync in the replication module uses eager-lock functionality which results in a more efficient performance of VM workloads.

For a complete list of major changes and features that are in GlusterFS 8, see the release notes for GlusterFS 8.0 at https://docs.gluster.org/en/latest/release-notes/8.0/. Subsequent update versions of GlusterFS 8.0 contain bug fixes which are listed in their respective GlusterFS 8.x release notes.

Likewise, the major changes and features that were released in GlusterFS 7 are listed in the release notes for GlusterFS 7.0 at https://docs.gluster.org/en/latest/release-notes/7.0/. Subsequent update versions of GlusterFS 7.0 contain bug fixes which are listed in their respective GlusterFS 7.x release notes.

Upgrade. Upgrade from Gluster Storage for Oracle Linux Release 6.x and 5.x. For reference, see https://docs.gluster.org/en/latest/Upgrade-Guide/upgrade-to-8/

1.2.2 Notable Updates and New Features in Release 6

New features and bug fixes in the upstream release of Gluster between Release 5 and 6 are available in the upstream documentation at:

https://docs.gluster.org/en/latest/release-notes/6.0/

In addition to the upstream changes, the following notable features are included in this release:

Introduction of support on Oracle Linux 8 with RHCK. This release introduces support for Gluster on Oracle Linux 8 when using the Red Hat Compatible Kernel (RHCK).
Support for Geo-replication. The geo-replication feature provides a facility to mirror data across geographically distributed clusters, similar to replicated volumes, but with the primary distinction being the focus on providing asynchronous replication for the purpose of disaster recovery. This feature can be used across a LAN, WAN or across the Internet. Since replication is asynchronous, the architecture follows a primary-secondary (previously, master-slave) model, where changes on the primary volume are replicated to a secondary volume. In the event of a disaster, data can be restored from a secondary volume.
Change to process to enable SMB or CIFS exports of Volumes. It is important to note that in previous versions all volumes were being exported by default via smb.conf in a Samba-CTDB setup. This had some negative implications in terms of performance and the unnecessary exposure of the CTDB lock volume. This release requires that volumes must be explicitly enabled for SMB or CIFS export before the volume is exported via Samba. The configuration remains the same, but an additional step to enable user.smb or user.cifs on the volume is required.
Upgrade. Upgrade from Gluster Storage for Oracle Linux Release 5, 4.1 and 3.12.

1.2.3 Notable Updates and New Features in Release 5

New features and bug fixes in the upstream release of Gluster between Release 4.1 and 5 are available in the upstream documentation at:

https://docs.gluster.org/en/latest/release-notes/5.0/

In addition to the upstream changes, the following notable features are included in Release 5:

Gluster block storage. Gluster volumes can be set up as an iSCSI backstore to provide block storage using the gluster-block and tcmu-runner packages. Files on volumes are exported as block storage (iSCSI LUNs). For more information, see Section 5.1, “Accessing Volumes by Using iSCSI”, and the upstream documentation at https://github.com/gluster/gluster-block.
Heketi scripted cluster automation. The heketi and heketi-client packages automate the management of your Gluster cluster. You can provision trusted storage pools and manage volumes using the heketi-cli command, and also write your own custom scripts using the API functions exposed by the Heketi service. It is particularly useful for cloud-based deployments where set up steps can be automated without requiring any manual systems administration. For more information, see Chapter 6, Automating Volume Lifecycle with Heketi, and the upstream documentation at https://github.com/heketi/heketi.
Upgrade. Upgrade from Gluster Storage for Oracle Linux Release 6 and Release 3.12.

1.2.4 Notable Updates and New Features in Release 4.1

New features and bug fixes in the upstream release of Gluster between Release 3.12 and 4.1 are available in the upstream documentation at:

https://docs.gluster.org/en/latest/release-notes/4.1.0/

In addition to the upstream changes, the following notable features are included in Release 4.1:

NFS access with NFS-Ganesha. You can expose volumes using NFS-Ganesha. NFS-Ganesha is a user space file server for the NFS protocol. It provides a FUSE-compatible File System Abstraction Layer (FSAL) to allow access from any NFS client.
Upgrade. Upgrade from Gluster Storage for Oracle Linux Release 3.12.

1.3 Technical Preview Features

This section contains information on technical preview features available in the major releases of Gluster Storage for Oracle Linux.

1.3.1 Technical Preview Features in Release 8

The following items are highlighted as technical preview features in Release 8 of Gluster Storage for Oracle Linux. For reference, see https://docs.oracle.com/en/operating-systems/oracle-linux/gluster-storage/gluster-intro.html#gluster-tech-preview-8.

Ansible Modules. Ansible modules for Gluster are made available in this release for use within the context of Oracle Linux Virtualization Manager. These modules are available as a technical preview for use outside of Oracle Linux Virtualization Manager and remain unsupported when used in this way.

The Gluster Ansible module RPMs are included for this purpose:
- gluster-ansible-cluster
- gluster-ansible-features
- gluster-ansible-infra
- gluster-ansible-maintenance
- gluster-ansible-repositories
- gluster-ansible-roles
The following RPMs are included as dependencies and are also unsupported outside of the context of Oracle Linux Virtualization Manager:
- ansible
- sshpass
- python-httplib2
- python2-jemspath

1.3.2 Technical Preview Features in Release 6

The following items are highlighted as technical preview features in Release 6 of Gluster Storage for Oracle Linux:

Ansible Modules. Ansible modules for Gluster are made available in this release for use within the context of Oracle Linux Virtualization Manager. These modules are available as a technical preview for use outside of Oracle Linux Virtualization Manager and remain unsupported when used in this way.

The Gluster Ansible module RPMs are included for this purpose:
- gluster-ansible-cluster
- gluster-ansible-features
- gluster-ansible-infra
- gluster-ansible-maintenance
- gluster-ansible-repositories
- gluster-ansible-roles
The following RPMs are included as dependencies and are also unsupported outside of the context of Oracle Linux Virtualization Manager:
- ansible
- sshpass
- python-httplib2
- python2-jemspath
GlusterD-2.0. GlusterD-2.0 (glusterd2), the thin management layer for Gluster with container orchestration systems, remains a technical preview in Release 6. GlusterD-2.0 is a re-implementation of glusterd. glusterd2 purports to have better consistency, scalability and performance when compared with the current glusterd, while also being more modular, easing extensibility. glusterd2 provides a new management daemon, REST API, and REST client application (glustercli). For more information, see the upstream documentation at https://github.com/gluster/glusterd2.

1.3.3 Technical Preview Features in Release 5

The following items were highlighted as technical preview features in Release 5 of Gluster Storage for Oracle Linux:

GlusterD-2.0. GlusterD-2.0 (glusterd2) is a re-implementation of glusterd. glusterd2 purports to have better consistency, scalability and performance when compared with the current glusterd, while also becoming more modular and easing extensibility. glusterd2 provides a new management daemon, REST API, and REST client application (glustercli). For more information, see the upstream documentation at https://github.com/gluster/glusterd2.

1.3.4 Technical Preview Features in Release 4.1

The following items were highlighted as technical preview features in Release 4.1 of Gluster Storage for Oracle Linux.

Heketi scripted cluster automation. The heketi and heketi-client packages automate the management of your cluster. You can provision trusted storage pools and manage volumes using the heketi-cli command, and also write your own custom scripts using the API functions exposed by the Heketi service. It is particularly useful for cloud-based deployments where setup steps can be automated without requiring any manual systems administration. For more information, you can read the upstream documentation at https://github.com/heketi/heketi.