Block storage subsystems are provisioned on the cluster as views. To create a subsystem, you create a view on an empty directory path and enable Block as an access protocol for the view. Views that are block-enabled are configured on dedicated paths that are not accessible to other protocols.
In order to make volumes available to block hosts, the volumes must be assigned, or mapped, to the hosts.
Configuration Components
The components of block storage configuration are:
Subsystems. A subsystem is an NVMe container for volumes, or namespaces. It is configured with a unique NVMe identifier, an NQN, which makes it discoverable by hosts as a remote block storage device. A subsystem on VAST Cluster is configured as a block-enabled view on a dedicated path.
Volumes. Volumes are units of capacity that can be provisioned on a subsystem. Each volume has a path relative to the subsystem path. The path can be backed up with snapshots. Snapshots of volumes can also be presented as volumes to hosts.
Hosts. NVMe/TCP hosts must be defined on the cluster with their NQN, a unique identifier created on each host by the NVMe/TCP client host configuration.
Configuration Workflow
Follow this workflow to create a subsystem, provision volumes and make them available to hosts:
Create subsystem(s) by creating a view and enabling only the Block protocol on that view. See Creating a Block Storage Subsystem (View).
Note
Avoid nesting the view under views that are accessible to other client protocols such as NFS or SMB, since clients will see the volume as a directory without being able to access it.
Create volume(s) on a subsystem.
Add the hosts to the cluster.
Map hosts to volumes. You can map multiple hosts to a volume or map multiple volumes to a host.
Managing Subsystems
Creating a Block Storage Subsystem (View)
A block subsystem is created on the cluster as a view with Block as the sole enabled access protocol. Create the view on an empty directory path.
Subsystems may not be nested one under another.
Creating a Block Subsystem with the VAST Web UI
In the VAST Web UI, select Element Store from the left navigation menu and then select Views.
Click Create View to add a new view.
The Add View dialog appears.
In the General tab, complete the following fields:
Tenant
If the cluster has multiple tenants, select the tenant on which you want to create the subsystem.
Path
Enter the full path from the tenant root to the directory that you want to create and allocate to the subsystem.
The directory will be created when the view is created. It must not be a pre-existing directory. It also must not reside under a path that is already used for block storage. It is also advisable not to create it under a path that is exposed to other protocols, since clients accessing that path may see the subsystem directory without being able to access it.
Protocols
Select Block. All other protocols are disabled when you select Block.
Policy name
Specify a view policy configured with the tenant and virtual IP pools that you want to use for the view.
Tip
The following are the only view policy settings that are relevant to block view configuration:
Tenant
Virtual IP pools
Note
Up to 16 network paths are supported on client connections to block subsystem views. One virtual IP pool with protocol role is used per path.
All security flavor options are compatible with block-enabled views. None of the remaining view policy settings affects block storage.
Select an existing view policy from the dropdown, or click Add new Policy to create a new one and follow the procedure described in Creating View Policies.
Complete the Block fields:
Name
Enter a name for the subsystem. The name is incorporated into the generated subsystem NQN.
Subsystem NQN
This field is read-only. The value is generated after the name is defined.
It is the NVMe Qualified Name (NQN), a unique identifier, incorporating the subsystem name, used to identify the view as a remote NVMe storage target for block clients.
You can use this field to retrieve the subsystem NQN for connection from the client.
Define as the default view (subsystem)
Enable this option if you want to set the view to be the default subsystem view. The default subsystem view is used as a default if a block volume is created by VMS REST API without a view being specified.
Click Create.
The view is created. You can see it displayed in the Views tab.
Creating a Block Subsystem with the VAST CLI
Use the view create command:
Specify the path (
--path PATH). The path must be a new path.Use the
--policy-id IDparameter to specify a view policy.Tip
The following are the only view policy settings that are relevant to block view configuration:
Tenant
Virtual IP pools
Note
Up to 16 network paths are supported on client connections to block subsystem views. One virtual IP pool with protocol role is used per path.
All security flavor options are compatible with block-enabled views. None of the remaining view policy settings affects block storage.
Specify
--protocols BLOCKto configure block access to the path. Do not specify any other protocols.Use the
--nameparameter to specify a name for the subsystem (required for block views). The name must be unique within the tenant.
For example:
vcli: admin> view create --path /empty_new_dir --policy-id 2 --protocols BLOCK --name blocksystem1
Managing Block Volumes
Creating Volumes
Prerequisites
A subsystem (block-enabled view). See Creating a Block Storage Subsystem (View).
Creating Volumes Using the VAST Web UI
Navigate to the Volumes tab in the Element Store page.
Note
The Volumes and Hosts tabs appear only when there is at least one block-enabled view configured on the cluster.
Click Create Volume.
Select either Single volume to create one volume or Multiple volumes to create multiple volumes of the same size with the same name suffix.
If you selected Single volume, complete these fields:
Tenant
Select the tenant, if applicable (if the cluster has more than one tenant that has block-enabled views configured).
View
Select the block enabled view (subsystem) on which you want to provision the volume.
Name
Enter a path to the volume relative to the subsystem directory. The path should not begin with a slash ("/"). You can include slashes inside the path to indicate a hierarchy of directories. The path will be created under the subsystem path for the volume. Any directory hierarchy indicated by slashes will be created accordingly. For example, if you specify
b/c/dthe directories<subsystem_path>/band<subsystem_path>b/cwill be created if they do not yet exist, as well as the new directory<subsystem_path>/b/c/d.Capacity
Enter a number and select GB or TB from the dropdown.
Supported range: 1GB - 1000TB.
QoS policy
Select an existing volume QoS policy to be applied to the volume, or choose Add new policy to create one and assign it to the volume.
If you selected Multiple volumes, complete these fields:
Tenant
Select the tenant on which the subsystem under which you want to create a volume resides, if applicable.
View
Select the block-enabled view (subsystem) on which you want to provision the volumes.
Name
Enter a path to each volume including a base volume name. The path is relative to the subsystem directory. The path should not begin with a slash ("/"). You can include slashes to indicate a directory hierarchy. A path will be created under the subsystem path for each volume. Any directory hierarchy indicated by slashes will be created accordingly. For example, if you specify
b/c/dthe directories<subsystem_path>/band<subsystem_path>b/cwill be created if they do not yet exist, as well as the new directory<subsystem_path>/b/c/d.See also Suffix.
Capacity
Enter a number and select GB or TB from the dropdown.
Supported range: 1GB - 1000TB.
Suffix
Optionally enter a suffix to be appended to the name for each volume. An incremental digit will also be added to each volume name.
Count
Enter the number of volumes you want to create.
QoS policy
Select an existing volume QoS policy to be applied to the volumes, or choose Add new policy to create one and assign it to the volumes.
Note
For volumes that share the same subsystem, ensure that all of the subsystem volumes have the same QoS limits set, or all of them do not have a QoS policy assigned, to prevent possible host IO performance impact.
In the Tags section, optionally add tags in the format key=value. These are applied to the volume(s) and can be used to add identifying information for organizational purposes. Hosts can also be tagged. You can also add tags later by modifying each volume.
To enter a tag, enter the key string in the Key field and the value string in the Value field, and then click Add Tag. Repeat as needed to add more tags.
Click Create.
Volume creation begins and can be monitored in the Activities page.
The volumes are listed in the Volumes tab.
If you created multiple volumes, a progress dialog appears showing you the progress of volume creation. You can either leave it open, in which case it will show the progress and let you know when the task is done, or click one of the other options provided:
Go to activities, to monitor the process from the Activities page.
Go to Volumes Table, to go back to the Volumes tab. The new volumes will be added to the table as they are created.
If you leave it open, when the task is done, another option, Map To Volumes Table, appears. You can click this option to configure mappings of the volumes to hosts.
Creating a Volume Using the VAST CLI
To create a volume using the VAST CLI, use the volume create command.
Displaying Volume Properties
Displaying Volume Properties in the VAST Web UI
The Volumes tab on the Element Store page can display the following columns for each volume configured on the cluster and each snapshot volume created by mapping a volume's snapshot to one or more block host(s).
Note
The Volumes and Hosts tabs appear only when there is at least one block-enabled view configured on the cluster.
Note
Not all columns are displayed by default. To adjust the selection of columns, click
.
ID | The VMS ID of the volume. Use this ID to reference the volume when running CLI commands. |
Name | The name of the volume. |
Tenant | The tenant where the volume resides. |
Full Path | Full path to the volume (including the subsystem name). |
Tags | The tags assigned to the volume, if applicable. |
Namespace ID | For mapped volumes, this is the namespace ID as used by hosts to search the volume within the subsystem. Each namespace ID is unique within the subsystem. If a volume snapshot is mapped to any host(s), a snapshot volume is created with its own namespace ID. |
NGUID | The NGUID used by block hosts to access the volume. |
UUID | The UUID, used by hosts to search the volume in the subsystem. |
Subsystem | The subsystem to which the volume belongs. |
Live Monitor | Indicates whether live monitoring is enabled for the volume. |
QoS | The volume QoS policy assigned to the volume. |
Size | The amount of capacity allocated to the volume. |
Snapshot ID | For snapshot volumes only, the ID of the snapshot that was mapped to create the volume. |
Creation Time | The date and time when the volume was created. |
Assigned Hosts | Block hosts that are mapped to the volume. The volume is available to these hosts. |
Displaying Volume Properties in the VAST CLI
To list volumes: blockhost list
To display properties of a specific volume: blockhost show
Modifying a Volume
After creating a volume, you can change the volume name, you can increase the volume size and you can add and remove tags.
Modifying a Volume from the VAST Web UI
In the Volumes tab on the Element Store page, right-click the volume you want to modify and select Edit.
Make changes as needed to the fields provided:
Name
Modify the volume name.
Capacity
Increase the capacity of the volume.
Supported range: 1 GB - 1000 TB.
QoS policy
Select an existing volume QoS policy to be applied to the volume, or choose Add new policy to create one and assign it to the volume.
Note
For volumes that share the same subsystem, ensure that all of the subsystem volumes have the same QoS limits set, or all of them do not have a QoS policy assigned, to prevent possible host IO performance impact.
In the Tags section, optionally add or remove tags.
To add a tag, enter a key string in the Key field and a value string in the Value field, and then click Add Tag. Repeat as needed to add more tags.
To remove a tag, click the deletion button for the tag.
Click Update.
The volume is modified.
Modifying a Volume from the VAST CLI
To modify a volume: volume modify
Deleting a Volume
Caution
Deleting a volume deletes the volume directory and all data on the volume.
Volumes must be unmapped from hosts before being deleted. You can choose to force unmap when you delete a single volume.
Deleting a Volume from the VAST Web UI
Right-click the volume and select Remove.
Caution
Do not use the Remove option to delete a snapshot volume. Deleting a snapshot volume deletes the source volume and all of its data. Instead, to delete a snapshot volume, unmap it from any mapped hosts. This automatically deletes a snapshot volume.
If you want to force the deletion even if the volume is mapped to hosts, enable the Force slider.
Note
There is no force option for bulk volume deletion. You must unmap hosts from volumes before bulk deleting them.
Click Delete Volume.
Deleting a Snapshot Volume
To delete a snapshot volume, unmap the volume from any mapped hosts. When you unmap hosts from a snapshot volume, the snapshot volume is automatically deleted without the volume itself, if it still exists, being deleted.
Caution
Do not use the Remove option to delete a snapshot volume. Deleting a snapshot volume deletes the source volume and all of its data.
Deleting a Volume from the VAST CLI
Use the volume delete command.
Monitoring Volumes
VAST Cluster allows for live monitoring of block volumes.
To enable or disable live monitoring for a volume:
In VAST Web UI, right-click the volume in the Element Store -> Volumes page and select Toggle Monitoring to toggle monitoring on or off.
In VAST CLI, run the
volume modifycommand with the--enable-live-monitoringordisable-code-monitoringoption specified.
Managing Block Hosts
Creating Block Hosts
Prerequisites
A subsystem (block-enabled view). See Creating a Block Storage Subsystem (View).
The host must be configured to interact with NVMe devices.
For Linux hosts, install the NVMe CLI tool:
sudo yum install nvme-cliVMWare hosts have built-in NVMe/TCP support starting from vSphere 7.0 Update 3.
The NVMe Qualified Name (NQN) of each host.
To get the NQN of a Linux host, use this command:
cat /etc/nvme/hostnqnTo get the NQN of a VMWare host, use this command:
esxcli nvme info get
Creating Block Hosts Using the VAST Web UI
Navigate to the Hosts tab in the Element Store page.
Note
The Volumes and Hosts tabs appear only when there is at least one block-enabled view configured on the cluster.
Click Create Host.
Select either Single host to create one host or Multiple hosts to create multiple hosts.
If you selected Single host, complete these fields:
Tenant
Select the tenant, if applicable (if the cluster has more than one tenant that has block-enabled views configured).
Name
Enter a host name. The host name must be unique on the tenant.
Connectivity type
This field is read-only, since only connectivity over TCP is supported in the current version.
NQN
Enter the host's NVMe Qualified Name (NQN), a unique identifier used to identify the host in NVMe operations.
Notice
Host NQN must be unique on the tenant.
On newly installed clusters, host NQN must be unique on the cluster, across all tenants.
In multi-tenant clusters, it is possible to leverage unique host NQN enforcement to resolve the target tenant of client requests according to the requested host NQN. For details of this feature, see Overview of Block Storage on VAST Cluster.
Note
You can add the same host to multiple tenants using its identifier.
If you selected Multiple hosts, complete these fields:
Tenant
Select the tenant on which the subsystem to which you want to add the host, if applicable.
Name
Enter a name string for all of the hosts. An incremental digit will be added to each host name.
Connectivity type
This field is read-only, since only connectivity over TCP is supported in the current version.
NQN
Enter a base value for the NVMe Qualified Names (NQNs) of the hosts. This is an identifier used to identify each host in NVMe operations. An incremental digit (and optionally a common suffix set by the Suffix field, will be added to each host's NQN. Each host will need to be configured to use the same NQN to connect to the subsystem.
Suffix
Optionally enter a suffix to be appended to the name for each host.
Count
Enter the number of hosts you want to create.
In the Tags section, optionally add tags in the format key=value. These are applied to the host(s) and can be used to add identifying information for organizational purposes. Volumes can also be tagged. You can also add tags later by modifying each host.
To enter a tag, enter the key string in the Key field and the value string in the Value field, and then click Add Tag. Repeat as needed to add more tags.
Click Create.
Host creation begins and can be monitored in the Activities page.
The hosts are listed in the Hosts tab.
If you created multiple hosts, a progress dialog appears showing you the progress of hostcreation. You can either leave it open, in which case it will show the progress and let you know when the task is done, or click one of the other options provided:
Go to activities, to monitor the process from the Activities page.
Go to Hosts Table, to go back to the Hosts tab. The new hosts will be added to the table as they are created.
If you leave it open, when the task is done, another option, Map To Hosts Table, appears. You can click this option to configure mappings of volumes to the hosts.
Creating Block Hosts Using the VAST CLI
To create block hosts using the VAST CLI, use the blockhost create command.
Displaying Block Host Properties
Displaying Block Host Properties in the VAST Web UI
The Hosts tab on the Element Store page can display the following property columns for each block host added to the cluster.
Note
The Volumes and Hosts tabs appear only when there is at least one block-enabled view configured on the cluster.
Note
Not all columns are displayed by default. To adjust the selection of columns, click
ID | The VMS ID of the host. Use this ID to reference the host when running CLI commands. |
Name | The name of the host. |
Tags | Any tags assigned to the host, if applicable. |
NQN | The host's NVMe Qualified Name (NQN), a unique identifier used to identify the host in NVMe interactions. |
Tenant | The tenant to which the host belongs. |
Assigned Volumes | The volumes to which the host is assigned. These volumes are available to the host when the host connects to the subsystem and searches volumes. |
Connectivity Type | The type of connectivity used by the host to connect to the subsystem. This is TCP for all block hosts in this version. |
Displaying Block Host Properties in the VAST CLI
To list block hosts: blockhost list
To display properties of a specific block host: blockhost show
Deleting a Host
Hosts must be unmapped from volumes before being deleted. You can choose to force unmap a host in order to delete it.
Deleting a Host from the VAST Web UI
Right-click the host and select Remove.
If you want to force the deletion even if the host is mapped to volumes, enable the Force slider.
Click Delete Host.
Deleting a Host from the VAST CLI
Use the blockhost delete command.
Assigning Block Hosts to Volumes
Assigning a block host to a volume enables the host to discover the volume. Assignments are managed by a mapping of hosts to volumes on the same tenant.
Managing Host-Volume Mappings in the VAST Web UI
To manage the mapping of hosts to a volume:
In the Volumes tab, right-click the volume and select Manage Mappings.
Details of block hosts are listed. Hosts that are already mapped to the volume are selected.
Select any hosts that you want to assign to the volume. Deselect any hosts that you want to unmap from the volume.
Click Save Mapping.
The mapping task begins and you can track it in the Activities page.
When the mapping is complete, you can see:
which hosts are assigned to a volume in the Assigned Hosts column of the Volumes tab.
which volumes are assigned to a host in the Assigned Volumes column of the Hosts tab.
Managing Host-Volume Mappings in the VAST CLI
To view mappings: blockmapping list, blockmapping show
To map one or more block hosts to a volume: blockmapping map_volume_to_hosts
To map one or more volumes to a host: blockmapping map_host_to_volumes
To unmap one or more volumes from a host: blockmapping unmap_host_volumes
To unmap one or more hosts from a volume: blockmapping unmap_volume_hosts
Presenting Volume Snapshots to Hosts
You can make a backup of a block volume accessible to hosts by mapping the host to a snapshot of the volume. This can be any snapshot on the volume path or on a path that includes the volume path. It can be a snapshot taken manually or from a local protected path.
When you assign hosts to a snapshot of a volume, VMS generates a globally unique UUID and namespace ID that is unique within the subsystem and assigns it to the mapping, enabling the assigned hosts to access the snapshot as a read-only volume. (These identifiers are destroyed if all hosts are unmapped from the snapshot.)
Snapshots that are mapped to hosts cannot be deleted.
If a volume is deleted, but you have the volume backed up by a snapshot, you can make the data available by mapping the volume to host from the snapshot. You need to know the name of the volume that was deleted.
Assigning Hosts to Volume Snapshots from the VAST Web UI
In the Volumes tab, right-click the volume and select Manage Mappings.
Select the hosts that you want to map to the snapshot.
Click Available volume snapshots.
All available snapshots of the volume are shown. You can see the ID, Name, Path and Creation Time of each snapshot.
Select the snapshot from which you want to map the volume to the selected host(s).
Click Save And Go To Mapping.
Click Save Mapping.
The mapping task begins and you can track it in the Activities page.
When the mapping is complete, you can see details of the new snapshot volume in the Volumes tab, where the Snapshot ID column identifies the snapshot.
Mapping a Volume from a Snapshot
You can also map a snapshot volume from a snapshot.
In the Data Protection page, select the Snapshots tab.
Find the snapshot that you want to use. This can be a specific snapshot of the volume path or a snapshot of the subsystem path or a snapshot of a path under the subsystem that includes the volume.
Right-click the snapshot and select Map Snapshot Volumes.
The Map Volumes dialog suggests volumes.
In the Map Volumes dialog, select the volume you want to map from the snapshot.
Note
It's possible that volumes that are not actually included in the snapshot will be suggested. Make sure the volume you want resides under the snapshot path before you proceed.
Click Next.
Select the volume path on the left and the host(s) on the right.
Click Save Mapping.
The mapping task begins and you can track it in the Activities page.
Mapping a Volume from a Snapshot after the Volume was Deleted
If the volume has been deleted but there is a snapshot of the volume and you want to enable a host to access the backup from the snapshot, you can use the following procedure. You will need to know the name of the volume and to which subsystem it belonged.
In the Data Protection page, select the Snapshots tab.
Find the snapshot that you want to use. This can be a specific snapshot of the volume path or a snapshot of the subsystem path or a snapshot of a path under the subsystem that includes the volume.
Right-click the snapshot and select Map Snapshot Volumes.
In the Map Volumes dialog, click Add volumes manually. (This appears at the top left of the table.)
From the Subsystem dropdown, select the subsystem under which the volume existed before it was deleted.
In the Volume Name field, enter the volume name.
Click Add to table.
Select the new row that was added to the table.
Click Next.
Select the volume path on the left and the host(s) on the right.
Click Save Mapping.
The mapping task begins and you can track it in the Activities page.
Assigning Hosts to Snapshot Volumes from the VAST CLI
To list block hosts: blockhost list. For example:
vcli: admin> blockhost list
+----+-----------+------------+----------------------------------------------------------------------+------+-------------+
| Id | Tenant-id | Name | Nqn | Tags | Tenant-name |
+----+-----------+------------+----------------------------------------------------------------------+------+-------------+
| 2 | 1 | blockhost1 | nqn.2014-08.org.nvmexpress:uuid:4c4c4544-004e-3310-804d-c6c04f4b3234 | {} | default |
+----+-----------+------------+----------------------------------------------------------------------+------+-------------+To list volumes: volume get_snapshots. For example:
vcli: admin> volume list
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+
| Id | View-id | Name | Size(GB) | Tags | Namespace-id | Nguid | Uuid | Capacity(GB) | Snapshot-id | Tenant-name |
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+
| 3 | 3 | dev/mgmt | 1.000 | {} | None | f88cd191-8c87-2686-806e-6538ae910f9f | f88cd191-14f7-4c86-806e-6538ae910f9f | 0.000 | N/A | default |
| 1 | 3 | dev/platform | 1.000 | {'team': 'platform', 'owner': 'DG'} | 1 | b1ee2839-8c87-26ab-982d-e4bf5541273b | b1ee2839-0fc4-4dab-982d-e4bf5541273b | 0.000 | N/A | default |
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+To list available snapshots of a volume: volume get_snapshots. For example, referencing the volume ID from the volume list output:
vcli: admin> volume get_snapshots --id 3035
+------+-----------+-------------+---------------------+
| Id | Name | Path | Created |
+------+-----------+-------------+---------------------+
| 1187 | snap | /try5/ | 2025-09-30 05:37:53 |
| 1189 | snap2 | /try5/cli1/ | 2025-09-30 05:40:01 |
+------+-----------+-------------+---------------------+
To assign hosts to a snapshot of a volume, use blockmapping map_volume_path. You will need the full volume path, formed by concatenating the view path and the volume name. For example:
vcli: admin> view show --id 3
+---------------------------------+---------------------------------------------------------------------------------------------------+
| ID | 3 |
| Path | /myblocksystem
...
vcli: admin> volume list
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+
| Id | View-id | Name | Size(GB) | Tags | Namespace-id | Nguid | Uuid | Capacity(GB) | Snapshot-id | Tenant-name |
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+
| 3 | 3 | my/volume | 1.000 | {} | None | f88cd191-8c87-2686-806e-6538ae910f9f | f88cd191-14f7-4c86-806e-6538ae910f9f | 0.000 | N/A | default |
| 1 | 3 | dev/platform | 1.000 | {'team': 'platform', 'owner': 'DG'} | 1 | b1ee2839-8c87-26ab-982d-e4bf5541273b | b1ee2839-0fc4-4dab-982d-e4bf5541273b | 0.000 | N/A | default |
+----+---------+--------------+----------+-------------------------------------+--------------+--------------------------------------+--------------------------------------+--------------+-------------+-------------+
vcli: admin> blockmapping map_volume_path --volume-full-path /myblocksubsystem/my/volume --snapshot-id 6 --blockhost-ids 2,3,4