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Creating a System Snapshot

 

You can use the System Snapshot feature to create a snapshot of the system state and roll back the system to a predefined state. The snapshot includes all persistent data on the hard disk including data in the database, system and application configuration files, and application and Linux executables. The System Snapshot is a fabricwide operation that maintains consistency across all nodes in the fabric.

Typically, you use the System Snapshot feature for rolling back the system when it is in an unrecoverable error-state due to corruption of system files, interruption of critical processes, and so on. You can also roll back the system to an older release if the system exhibits undesirable behaviors after a software version upgrade.

Tip

We recommend using System Snapshot before performing significant actions (for example, adding a node to the Junos Space fabric) that have the potential to precipitate the system into an undesirable state. You can delete the snapshot after you have verified that these actions were performed successfully.

System Snapshot is currently supported on a Junos Space fabric that consists of only Junos Space virtual appliances or only Junos Space appliances. This feature is not supported on a hybrid fabric consisting of both Junos Space virtual appliances and Junos Space appliances.

System Snapshot does not impact the performance of a Junos Space virtual appliance. However, if you are using a Junos Space Appliance, performance may be impacted by the number of write operations performed to the snapshot’s logical volume.

The maximum size that a snapshot can occupy for Junos Space Network Management Platform is 300 GB. The maximum size that a snapshot can occupy for Junos Space Platform migrated from releases prior to 11.3 is 43 GB. On the Junos Space Appliance, the snapshot becomes invalid if it has been kept for a long time because usage of the snapshot volume disk space increases as write operations continue. When the usage reaches the maximum size of snapshot volume, the snapshot is disabled. Therefore, ensure that you clear enough hard disk space to accommodate the snapshot.

After executing these commands, start creating the snapshot. The steps used to create a system snapshot for a Junos Space virtual appliance and a Junos Space appliance are almost identical, but there are two additional preliminary steps for the Junos Space virtual appliance:

If you are working with a Junos Space virtual appliance, perform the following steps before taking the system snapshot:

Note

The following procedure is valid only on a Junos Space virtual appliance deployed on a VMware Elastic Sky X (ESX) or ESXi server.

  1. In the Fabric page (Administration > Fabric), and set the ESX configuration for every node in the fabric. For more information, see Configuring the ESX or ESXi Server Parameters on a Node in the Junos Space Fabric.
  2. Install the VI Toolkit for Perl provided by VMware. For more information, see Installing VI Toolkit for Perl on Junos Space Virtual Appliance.

To create a system snapshot:

  1. Select Administration > Fabric

    The Fabric page appears.

  2. Click the System Snapshot icon.

    The System Snapshot dialog box appears. You can see a system snapshot if you have taken a snapshot earlier. If you are taking the snapshot for the first time, you will not see any snapshots in this dialog box.

    Note

    If you are creating a system snapshot when a snapshot already exists, the new snapshot will overwrite the older snapshot. Currently, Junos Space Platform can store only one system snapshot.

  3. Click Take Snapshot.

    The System Snapshot Confirmation dialog box appears.

  4. Enter the name of the snapshot in the Snapshot Name field.
  5. Enter the comments in the Comment field.
  6. Click Confirm.

    A new job is created and the job ID appears in the System Snapshot Job Information dialog box.

  7. Click the job ID to view more information about the job created. This action directs you to the Job Management workspace.

    The time taken to complete the snapshot job for a Junos Space virtual appliance is dependent on the number of nodes in the fabric, the disk size of the virtual appliance deployed, the memory size of the virtual appliance, and the performance of the ESX server. The time taken to complete the snapshot job for a Junos Space Appliance is dependent on the disk space used on the appliance.

Note

You may not be able to create a snapshot of the system state if any of the following conditions is true:

  • There is insufficient disk space on the ESX servers.

  • One of the ESX servers has been incorrectly configured.

  • One of the nodes is down.

  • The fabric consists of both Junos Space virtual appliances and Junos Space appliances.

  • The name specified for the current snapshot is the same as that of the stored snapshot.