XenCenter

Storage properties

Note:

XenCenter 2023.x.x is currently in preview and is not supported for production use. Note that any future references to production support apply only when XenCenter 2023.x.x and XenServer 8 go from preview status to general availability.

You can use XenCenter 2023.x.x to manage your XenServer 8 and Citrix Hypervisor 8.2 CU1 non-production environments. However, to manage your Citrix Hypervisor 8.2 CU1 production environment, use XenCenter 8.2.7. For more information, see the XenCenter 8.2.7 documentation.

You can install XenCenter 8.2.7 and XenCenter 2023.x.x on the same system. Installing XenCenter 2023.x.x does not overwrite your XenCenter 8.2.7 installation.

Viewing storage properties

You can view the details for all storage repositories (SRs) in your XenServer pool from the Storage tab of the pool. Select a server or pool in the Resources pane and then click the Storage tab. This tab displays information about the local and shared storage repositories. This information includes the name, description, storage type, usage, the size of the SR, and the virtual allocation.

To view detailed information about an individual storage repository, select the SR repository in the Resources pane. In the main pane, the following tabs are available: General, Storage, and Search.

General

The General section of the General tab displays the information about the storage repository. This information can include the name, description, any tags applied to the SR, the folder the SR is in, storage type, the size of the SR, the SCSI ID, and the UUID of the SR.

Note

For GFS2 SRs, the size is displayed in the form “a GB used of b GB total (c GB allocated)”. The values in this statement have the following meanings:

  • c is the space that is allocated and used in the SR. (If you run the du command, this is the value shown.)
  • b is the actual total size of the LUN.
  • a is the ‘used’ space. This value is the sum of the file sizes for the files on the SR and does not take into account blocks that have been freed from sparse files. These freed blocks can now be used by other VMs. (If you run the df command, this is the value shown.)

    On GFS2 SRs, the VM disks are stored in the QCOW2 format, which is both thinly provisioned and sparse. When data blocks are deleted from the VM the associated data blocks in the VM disk file are freed back to the SR filesystem and marked as unallocated, but the file size is unchanged. This behavior can cause discrepencies between the value of a and the value of c.

The Status section lists the state of the SR and shows whether it is connected to servers in the pool.

The Multipathing section shows whether multipathing is active between the SR and servers in the pool.

Storage

The Storage tab lists the virtual disks located on the storage repository. For each disk, the table shows the disk name, description, size, virtual machine name, and whether changed block tracking is enabled.

Using the Search tab, you can construct queries based on object types, folders, and attributes. For more information, see Searching Resources.

Changing SR properties

The Properties dialog box allows you to modify the details of your SRs and manage them effectively by organizing the resources using folders, tags, and custom fields. It also allows you to configure alerts when the storage throughput exceeds specific limits.

You can access the Properties dialog box for an SR in one of the following ways:

  • Select a server or pool in the Resources pane and then click the Storage tab. This lists the local and shared storage in your pool. Select an SR from the list and click Properties.
  • Select the storage repository in the Resources pane. In the General tab for the SR, click Properties.

General

The General tab allows you to change the name and description of the SR, and manage its folder and tags:

  • To change the name of the SR, enter a new name in the Name box.
  • To change its description, enter new text in the Description box.
  • To place the SR in a folder or to move it to a different folder, click Change in the Folder box and select a folder. For more information, see Using folders.
  • To tag and untag the SR and to create and delete tags, see Using tags.

Custom fields

Custom fields allow you to define or modify any additional information about the SR. This tab helps you to search and effectively organize your storage repositories. For more information, see Using custom fields.

Alerts

The Alerts tab allows you to configure alerts when the total read and write storage throughput activity on a Physical Block Device (PBD) exceeds the specified limit. Check Generate storage throughput alerts and set the storage throughput and time threshold that triggers the alert.

Note:

Physical Block Devices (PBD) represent the interface between a specific XenServer host and an attached SR. When the total read/write SR throughput activity on a PBD exceeds the threshold you have specified, alerts are generated on the host connected to the PBD. Unlike other host alerts, this alert must be configured on the relevant SR.

Read Caching

On the Read Caching tab, you can choose to enable or disable read caching.

Read caching improves performance on NFS, EXT3/EXT4, or SMB SRs that host multiple VMs cloned from the same source. You might want to disable read caching in the following cases:

  • You have no file-based SRs
  • You do not have any cloned VMs
  • It is not providing any performance benefits

For more information, see Storage read caching.

Storage properties