Managing disks and swap space in a cluster

The disk configuration utility enables you to add disks, move BMC Discovery data onto new disks and create swap space on new disks on all of the machines in a cluster. All of the operations apply to the individual machine, you cannot move data around the cluster using this utility. However, the changes you make to the individual machines are coordinated, as when you make changes to disks on a cluster member, all members of the cluster need to be shut down.

To minimize cluster downtime, you configure and queue the changes on individual machines and then apply the changes. When you apply the changes, the cluster is shut down automatically and restarted when all of the changes have been applied to the individual machines.

As with a standalone appliance, the following restrictions apply:

  • You can only move data or create swap space on disks that are not currently used by BMC Discovery.
  • You cannot move more than one component of BMC Discovery data to a given target disk.
  • You cannot move the components back to the system disk after they have been moved to a secondary disk.

Back up your data before changing disk configurations

The disk management utility performs disk operations such as partitioning and moving data. All data on the new disks is deleted. When data is moved from the system disk, it is copied to the new disk and deleted from the system disk. Before using it you should always backup your cluster.

LVM is not supported

If you try to add an LVM disk, the operation fails and the following message is displayed:
Unexpected system configuration: LVM-based configuration detected

It is not possible to resize a filesystem using the UI. However, if you do need to resize a filesystem, you should contact Customer Support for guidance on doing so.

The following disk types are defined:

Disk type

Description

System Disk

The disk on which BMC Discovery is installed.

Additional Disk

Any additional disk which contains BMC Discovery data.

New Disk

Any additional disk with no mounted partitions. There must be 4000 MB free space on the disk after the copy operation or the operation is not permitted. If you are only creating swap space, the disk must be larger than the suggested swap size.

Non ADDM Disk

Any additional disk with mounted partitions. These partitions must be unmounted before this disk can be configured using the disk management utility.

The Disk Configuration page of a cluster member displays the following:

  • A panel which shows the queued changes for all members of the cluster
  • A drop-down list with links to the UI of each of the other cluster members
  • A panel which shows the current configuration of any disks in the appliance and the suggested configuration of any new disks
  • A comprehensive key to the data types and their representation

Configuration options for a new disk

After a physical (or virtual, in the case of a VM) disk has been added to the appliance and recognized by the operating system, it is displayed in the Disk Configuration window.

On any new disk, a Change Usage drop-down list is displayed which is populated with the data partitions on the system disk. Where there is insufficient space on the new disk to copy the data from a particular partition, that partition's label is disabled. The label is also disabled if the partition has already been selected to have its data moved to another disk.

You can also choose to add a swap partition to the disk by selecting the check box. The check box is only displayed if you have insufficient swap space configured. The disk configuration utility uses the following calculation to determine the best swap size.

  • Where the amount of memory is less than 16 GB, swap size is set at double the memory.
  • Where the amount of memory is between 16 and 32 GB, swap is set at 32 GB.
  • Where the amount of memory exceeds 32 GB, swap is set to equal the memory.

The add swap check box is not displayed if the available new disk does not have enough space to store the additional swap to reach the optimal swap size. For example, if the system has 8GB swap by default, and the optimal swap size is 24GB, then 16GB additional swap is required. If the new disk has only 12GB available, the check box is not displayed.

When you make the changes you have chosen or to accept the changes suggested by the system, the services are shut down and a progress indicator is displayed.

To move data to new disks on cluster members

After new disks have been added to cluster members and recognized by their individual operating systems, they are displayed in the Disk Configuration window of that machine's UI. To move data to the disk:

  1. Back up your cluster.
  2. From the main menu, click the Administration icon.
    The Administration page opens.
  3. In the Appliance section, click Disk Configuration.
    The Disk Configuration page opens.
  4. If the suggested configuration is what you want, continue this procedure from here.
  5. If you do not want to accept the suggested configuration, select Do not move any data here from Change Usage.
  6. Select the data to move to the new disk from Change Usage.

    Note

    If the disk is a non-ADDM disk, you must unmount all partitions on the disk before proceeding.

  7. Select the Add swap check box if you want to add additional swap space.
  8. Click Queue to add the changes to the Queued Changes for the Cluster list.
  9. Repeat from here for each member of the cluster that you need to make changes to. To access the other members of the cluster, select the link for the required member from the Go to another Cluster Member drop-down list.
  10. Review the Queued Changes for the Cluster list, and click one of the following options to continue:
    • Cancel all—To remove all queued changes for all machines from the list. You can then start the procedure again.
    • Cancel—To delete the queued request for the current machine and enable you to reconfigure it.
    • Start—To proceed.
    If you clicked Start, you are then requested for confirmation. The BMC Discovery services are stopped on all members of the cluster and all of the contents of the new disks on all members are deleted before moving data or creating swap partitions.
  11. Click OK to proceed.
    The status page is displayed on each cluster member UI which show a progress indicator and details of the individual operations.
    After the operation has been completed, the services are started on all members and the login page is displayed on each member's UI.

Note

If the only operation you perform is to add swap to a new disk, the services are not stopped and started and you do not need to log in, nor do you need to shut down the cluster.

When data is moved from an additional disk that contains only a data partition, at the end of processing, the disk is identified as a new disk and is displayed with a suggested configuration. The existing data is not deleted, although the partition is not mounted.

When data is moved from an additional disk that contains a data partition and a swap partition, at the end of processing, the disk is identified as a non-ADDM disk. The existing data is not deleted, although the partition is not mounted. To reuse this disk, disable the swap partition as shown here.

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