How to Recover a Lost Swarm Cluster Services (SCS) Instance Using a Backup File

1 Prerequisites
2 Steps for Recovery
3 Some Considerations Relating to Storage Node IP Addresses

Prerequisites

Before proceeding with the recovery, have the following items on hand:

The RPM for the desired SCS version and any related files required for SCS installation, as described here.
A copy of your most recent SCS backup. A full backup is required, and must be made with the same version of SCS being installed: SCS Administration | Full Backup
A copy of the Swarm storage bundle that matches the version of the Swarm storage software running on your storage cluster. This is not necessary if a full backup is used.
The administrator user name, administrator password, and cluster name of your storage cluster.
The DHCP initialization parameters used for the storage cluster (reserved IP address pool ranges).

VERY IMPORTANT

Make sure the newly configured SCS has the same private side SCS network address. There are parameters stored in the Persistent Settings Stream that point to this address. If you are restoring to a new SCS while the old SCS is still online, you may shut down the private side network interface on the old SCS so that there are no duplicate IP addresses.

Steps for Recovery

The installed SCS software must be the same version as was used to create the backup.

Step 1

Install SCS by following the instructions in Online SCS Installation.

Step 2

Run the SCS initialization wizard by following the instructions in Run the Swarm Cluster Services (SCS) Initialization Wizard.

Step 3

Verify that the version of SCS software is activated.

scsctl platform software list

Active the SCS software version if needed.

scsctl platform software activate

This will present a list of all available versions of the platform component. Verify that the correct version is marked as active (choose it from the list).

Step 4

Restore the SCS backup.

# scsctl backup restore [backup file name]

Step 4

Check the version of the Swarm storage component.

SCS will display a list of storage components. The active component will be identified in the list.

Case 1

Proceed to Step 5 if the Swarm storage version that is currently running on the storage cluster is shown as the active software version.

Case 2

Make the currently running version the active version in SCS if the Swarm storage version that is currently running on the storage cluster is not shown as the active software version.

Note

The software version provided as a parameter to the command shown above must match the listed version exactly, character by character. (Include the parentheses and string inside them in the parameter.). It is helpful to wrap this version string in quotation marks.

Case 3

If no components are listed or the software version running on the storage cluster is not shown in the list, add the version of the Swarm storage component to SCS that matches the version currently running on the storage cluster.

During this process, you will be asked whether to use encryption-at-rest with disk volumes and a name to use for the storage cluster.

Step 5

Check the administrator user name and administrator password.

Check the administrator user name configured in SCS.

Check the administrator password configured in SCS.

Proceed to Step 6 if both the administrator user name and the administrator password configured in SCS match the name and password configured in the current storage cluster.
Change the user name and/or password configured in SCS if either the administrator user name or the administrator password configured in SCS do not match the administrator user name and password configured in the current storage cluster.

Step 6

Initialize DHCP.

Some Considerations Relating to Storage Node IP Addresses

After restoring a current backup of an SCS instance, storage node IP addresses should retain the same IP addresses when they are rebooted, as long as the SCS backup file was created after all storage nodes were booted from the SCS instance (and those nodes were up and running). This includes the case where static IP addresses were manually set for the nodes in the storage cluster.

The IP addresses of storage nodes added to the storage cluster subsequent to the creation of the backup file will not have been recorded in the backup, and those nodes may acquire a different IP address when they are rebooted. (Although IP addresses will come from the same range of the address pool as long as DHCP is initialized with the same parameters.).

Ensure that nodes that had their IP addresses recorded in the backup are booted first. All other nodes may only be safely booted after these are online.