Having prepared the environment on both SoftNAS AWS instances, we can now set up high availability. The first step towards high availability in SoftNAS is to establish replication. SnapReplicate™ makes this as simple as completing a quick wizard.
To establish the secure SnapReplicate relationship between two SoftNAS nodes, simply follow the steps given below:
- Log into the source controller's (the first instance within which you created the CIFS enabled volume) SoftNAS StorageCenter™ administrator interface using a web browser.
- In the Left Navigation Pane, select the SnapReplicate™/SNAP HA™ option.
The SnapReplicate/SNAP HA page will be displayed.
- Click the Add Replication button in the Replication Control Panel.
The Add Replication wizard will be displayed. Read the instructions on the screen and then click the Next button.
- In the next step, enter the IP address or DNS name of the remote, target SoftNAS controller node in the Hostname or IP Address text entry box. Note that by specifying the replication target's IP address, you are specifying the network path the SnapReplicate™ traffic will take.
The source node must be able to connect via HTTPS to the target node (similar to how the browser user logs into StorageCenter using HTTPS). HTTPS is used to create the initial SnapReplicate configuration. Next, several SSH sessions are established to ensure two-way communications between the nodes is possible. This connection is established by providing the IP address.
- Next, provide the username (softnas) and the password (if default, this is the instance id) of the target instance. Type the password again to verify, then click Next.
The IP address/DNS name and login credentials of the target node will be verified. If there is a problem, an error message will be displayed. Click the Previous button to make the necessary corrections and then click the Next button to continue.
- Read the final instructions and then click the Finish button.
The SnapReplicate™ relationship between the two SoftNAS controller nodes will be established. The corresponding SyncImage of the SnapReplicate™ will be displayed.
After data from the volumes on the source node is mirrored to the target, once per minute SnapReplicate™ transfers keep the target node hot with data block changes from the source volumes.
The tasks and an event log will be displayed in the Replication Control Panel section. This indicates that a SnapReplicate™ relationship is established and that replication should be taking place.
Configuring SNAP HA™
SnapReplicate™ establishes a replication relationship, one that can be manually triggered or scheduled, but is not automated. For true high availability in a failover situation, SNAP HA™ must be configured as well.
- To configure SNAP HA™, complete the SNAP HA wizard, beginning by clicking Add SNAP HA™.
Note: Configuration of SnapReplicate™ is a prerequisite to setup of SNAP HA™. If SnapReplicate™ is not configured, the Add SNAP HA™ button will be grayed out.
If you have not yet configured a notification email, the opportunity to provide one will be presented prior to continuing SNAP HA™. Provide an email address for support reports and logs to be sent to, and click OK.
- Click Add SNAP HA™ once more if this occurs. The Add High Availability wizard will begin.
The next screen depends upon whether your storage pool has made use of MSFT disks added from within the SoftNAS UI (as explained in Adding Block Storage via the SoftNAS UI), or if you added Azure Blob Storage disks, or added your block storage disks through the Azure Portal.
If you added Azure Blob Storage or used the Azure Portal to add your disks, then you would first have to provide Azure account credentials before being prompted to enter your Virtual IP Address.
If (as directed in this guide) you added Microsoft disks using the SoftNAS UI, you will have supplied Azure credentials already. In this case, the wizard will skip ahead to the Virtual IP screen. This is because your credentials are cached in order to speed up the process.
- Here you will create and add an IP Address that is not in the same CIDR block as the instances. (In simplest terms, ensure that the IP address does not start with the same numbers as the two instances.) Click Next.
Click Finish on the Finish HA Setup screen.
- Your SNAP HA™ pairing is created.
To test, shut down one of the instances. The other will become primary after a few moments. Alternatively, select Actions, and Takeover to simulate a failover.