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Clusters Screen

7 minute read.

Last Modified 2024-03-19 09:09 EDT

TrueCommand 2.3 (and later), in conjunction with TrueNAS SCALE 22.12.0 (and later), can create and manage clusters, cluster volumes, and cluster volume shares.

This article describes the various screens used for clustering. If you want to create and integrate clusters, see Clustering and Sharing SCALE Volumes with TrueCommand.

Clusters are an experimental feature in TrueCommand. Before using such features, please back up all your data. Do not rely on this for critical data.

Clusters

The Clusters screen contains all options related to the cluster feature. To see this screen, log in to TrueCommand and click the Clusters icon in the upper left.

Option descriptions (click to expand)

If you have not created a cluster, there is a single option on this screen:

Setting	Description
CREATE CLUSTER	Opens the form to create a new cluster.

Create Cluster

The cluster creation options split into two pages: Systems and Confirmation.

Systems

The initial form has two fields:

Option descriptions (click to expand)

Setting	Description
Name	Enter a string to identify the cluster.
Systems	Dropdown list shows all connected TrueNAS SCALE systems available for this cluster. Clusters can consist of between 3 and 20 individual SCALE systems.

Making selections in the Systems field adds more options.

Figure 3: Network Options for Clustered Systems

Option descriptions (click to expand)

Setting	Description
Delete	Clicking the Delete icon removes the system from the cluster.
Network Address	Dropdown list shows available IP addresses to use for cluster traffic. Using private dedicated network addresses is recommended.

Confirmation

There is a single option on this page.

Figure 4: Review and create page for Clusters

Option descriptions (click to expand)

Setting	Description
CREATE	Begins creating the cluster, which restricts the SMB functionality on the SCALE systems.

Configure Cluster

Successfully creating a cluster adds a cluster widget to the Clusters screen and opens options to configure the new cluster. These options are split into four screens: VIPs, Associate VIPs, Active Directory, and Confirmation.

VIPs

The VIPs page has options and fields added for each SCALE system in the cluster.

Setting	Description
ADD	Adds another line under VIPs for IPs and netmasks.
Address	Virtual IP address for one of the cluster systems.
Netmask	Netmask for the IP address.

Associate VIPs

The Associate VIPs page allows you to select interfaces to assign to the VIPs.

Setting	Description
Interface	Select an interface from the dropdown list of interface options and assign it to the VIP.

Active Directory

The options on this page let you establish a connection between an Active Directory environment, SCALE systems, and TrueCommand.

Option descriptions (click to expand)

Setting	Description
Domain Name	Enter a string for the Microsoft Active Directory (AD) environment host name.
NetBIOS	Automatically populates with the cluster name.
Username	Enter a string for the account credential to establish the AD connection. You must use an account with administrative access.
Password	Enter a string for the account credential to establish the AD connection. You must use an account with administrative access.

Confirmation

All chosen settings display here for you to confirm before being applied to the cluster.

Configure Cluster: Review and confirm — Figure 8: Review and Confirm

Option descriptions (click to expand)

Setting	Description
CONFIRM	Saves the configuration settings and permanently apply them to the cluster.

Manage Clusters

Clusters display as standalone cards.

The card displays the name of the cluster, the current state, and the names of the systems used in the cluster (Nodes). Click the Options icon to see management options for the cluster. Click the ^ or v icons to minimize or expand (respectively) the list of nodes.

Option descriptions (click to expand)

Setting	Description
CREATE VOLUME	Opens the form to create new clustered storage.
Rename	Opens the form to enter a new Cluster Name.
Delete	Disconnects each SCALE system from the cluster and removes the card from TrueCommand. Shows a confirmation popup when clicked.

Cluster Volumes

Clicking CREATE VOLUME for an existing cluster shows options to configure new clustered storage. The options split into two pages: Details and Confirmation.

Details

Option descriptions (click to expand)

Setting	Description
Name	Enter a string as an identifying label for this cluster volume.
Type	Dropdown list. Select the layout and behavior for the volume.
Cluster	String (disabled). Shows the cluster that controls the new volume.
Brick Size	Enter an integer and select from the dropdown list to define storage capacity. Allows numeric values and selecting units of size.
Pools	Dropdown list. Select a storage pool on the individual SCALE system that provides capacity for the cluster volume.

The Type field has four options:

Replicated

Replicated volumes are the most similar to ZFS mirrors. They have exact copies of all data on all bricks. Since TrueNAS SCALE SMB cluster implementation requires a minimum of three nodes, a replicated volume has three identical copies of all data.

A replicated volume can experience multiple brick failures, yet you can still access the data if a single brick is still accessible. Replicated volumes excel in data reliability and data redundancy at the cost of lower overall storage.

Distributed Replicated

Distributed replicated volumes distribute files across replicated sets of bricks. You set the replica count during the initial volume configuration.

Distributed replicated volumes require a minimum of three replicas to avoid potential issues with split-brain. The number of bricks must be a multiple of the replica count. The minimum number of nodes for this volume type is six since each replica set requires three nodes.

Distributed replicated volumes are best when you need highly-available data with redundancy protection, although they scale poorly.

TrueCommand currently allows distributed replicated volumes with two replicas. This unintended behavior can lead to potential data loss due to split-brain situations. We are working to resolve this in TC-2626.

Dispersed

Dispersed volumes are most similar to RAIDZ. Data is striped across the bricks with parity added. You configure the number of redundant bricks during volume creation. The number of parity bricks determines the number of bricks the cluster can lose without impacting volume operation.

Confirmation

The Confirmation page shows details for the chosen volume Type and storage makeup of the new clustered volume.

Add Cluster Volume: Review and create — Figure 11: Review and Create

Option descriptions (click to expand)

Setting	Description
BACK	Click the button to go to the previous configuration page.
CREATE	Click the button to save the configuration and build the clustered volume on each system in the cluster.

Managing Cluster Volumes

Created cluster volumes display in the related cluster card.

Figure 12: Cluster Volume added to a Cluster

The card displays the name, used storage, and volume status. Click the volume name to expand the details and see more management options.

Option descriptions (click to expand)

Setting	Description
DELETE	Click the button to remove the volume from the cluster and destroy stored data.
CREATE SHARE	Opens the form to configure a new SMB share for remote access to this cluster volume.

Adding a cluster share shows a few options.

Option descriptions (click to expand)

Setting	Description
Cluster	String (disabled). Shows the name of the cluster related to this share.
Cluster Volume	String (disabled). Shows the name of the cluster volume to share.
Name	Enter a string to create a label for this new cluster share.
ACL	Dropdown list. Access Control List. Choose permissions for the share.
Readonly	Checkbox disables or allows file management options for connected users. Select to disable.
CONFIRM	Click the button to save the settings, create the share, and make the cluster volume accessible to Active Directory user accounts.

ACL Options

POSIX_OPEN - Grants read, write, and execute permissions to all users.
POSIX_RESTRICTED - Grants read, write, and execute to owner and group, but not others. The template may optionally include the special-purpose ‘builtin_users’ and ‘builtin_administrators’ groups and Domain Users and Domain Admins groups in Active Directory environments.

Managing Cluster Volume Shares

Click the cluster volume name to open the Cluster Volume Details and see any shares.

Option descriptions (click to expand)

Setting	Description
DELETE	Removes the share from the Cluster Volume. This operation does not destroy data.
CREATE SHARE	Opens the form to configure a new SMB share for remote access to this cluster volume.

Clusters Screen