This is the procedure to remove active EBoxes from a cluster. Use this procedure if you have older model devices that you wish to remove from the cluster, or excess capacity in the cluster.
The EBox removal process takes some time, depending on the amount of data used in the devices to be removed. During the process, all data in the devices is moved to other EBoxes in the cluster. Once this is done, the devices are deactivated and powered off, after which they can be removed from the cluster.
Once the removal process starts, it cannot be stopped. During the removal process, you cannot start another EBox removal process on other EBoxes, or start a EBox addition or migration process for other EBoxes. You can also not start any other data rewrite process.
At the beginning of the removal process, VMS validates whether the EBoxes can safely be removed from the cluster (for example, if there is sufficient storage remaining capacity for the data on the selected devices, and whether minimum constraints for EBox HA are maintained). If the validation is successful, the removal process begins. At this point, the overall capacity for the cluster is reduced by the amount of the devices to be removed. The Flash Write Buffer for the cluster is also disabled at this point, until the decommission process completes.
Prerequisites
The cluster must be in an Active state.
The cluster must have sufficient storage for the data in the removed EBoxes.
If rack resiliency is enabled for the cluster, the EBoxes that are removed must be balanced across all failure domains such that, after the removal, the domains still satisfy the balancing requirements (see here). Alternatively, the EBoxes that are removed constitute a single failure domain.
If the cluster was upgraded from an earlier version than 5.5, the metadata must be rewritten to the format used for EBox removal. This is done by running the metadata rewriter prior to the EBox remove (this is described below).
Removing an EBox using the VAST Web UI
On the VAST Web UI navigate to the Infrastructure page, and select the EBoxes tab.
Click Manage Infrastructure, and then select Remove EBoxes.
If your cluster has been upgraded from an earlier version than 5.5, you must perform a Metadata rewrite before proceeding with EBox removal. This converts metadata from a format used in earlier versions to a format used in the latest version. It does not change the data.
Click the link Run Metadata Table Rewrite, and then confirm the action. The metadata rewrite operation can take up to several hours, depending on the amount of data and the number of EBoxes. Check progress of this action in the top navigation bar (top right corner), in the Activities section. Only when this action is complete proceed with the next step.
Note:
The metadata table rewriter needs only to be run once on the cluster. It is not necessary for clusters installed initially with version 5.5 (or later). If the rewriter has been run, or the cluster is initially installed with 5.5 or later, you are not prompted to run the rewriter.
Select from the list the EBoxes to be removed, then click Remove EBoxes.
In the confirmation dialog, click Yes, Do, to confirm the removal for the selected devices. The EBox removal process starts.
Monitoring Progress of EBox Removal
The EBox removal process can take some time, depending on the number of EBoxes involved, and the amount of data that is moved to new devices.
You can monitor the progress of the process in the top navigation section (top right corner). Select Activities, and the look for EBox Removal.
Removing an EBox using the VCLI
To remove active EBoxes using the VCLI, use ebox decommission.
Note:
ebox decommissiondiffers fromebox remove.ebox removeis used to remove EBoxes that are not in use; it does not move data from the devices to other Eboxes.ebox decommissionis used to remove active EBoxes, after first moving its data to other active devices.