Virtual Disk Groups

In this topic:

About virtual disk groups

Creating groups

Adding virtual disks to existing groups

Serving groups to a host

Performing snapshot operations on groups

Performing rollback operations on groups

Performing replication operations on groups

Enabling/disabling sequential storage on groups

Renaming groups and virtual disks in groups

Removing virtual disks from groups

Deleting groups

Viewing group details

About Virtual Disk Groups

Virtual disks can be grouped in order to perform the same operations on all members of the group simultaneously. Any number of virtual disk groups can be created with an unlimited number of members, but any virtual disk can only be a member of one virtual disk group.

 General notes about group operations:

o           Virtual disk groups can contain virtual disks belonging to different servers in the same server group. In this case, each server will only recognize group members that were created from their own storage sources. Members of the virtual disk group will appear under their respective servers in the DataCore Servers Panel. Actions will only be performed on the applicable virtual disks in the group. In order for the same action to be performed for all virtual disks in the group, the action may have to be performed for more than one server (depending on the configuration of the virtual disks in the group). One such action is enabling Continuous Data Protection.

o           Group operations can impact performance. The impact depends on the type of operation and the number of virtual disks in the group.

o           Snapshots, Continuous Data Protection and Sequential Storage cannot be enabled on a virtual disk group if the group has a member that is a VVOL or protocol endpoint virtual disk.

Group operations include:

o           Serving the group to a host

o           Performing snapshot operations

o           Enabling/disabling Continuous Data Protection and performing rollback operations

o           Performing replication operations

o           Enabling/disabling sequential storage

o           Renaming virtual disks in a group

Creating Groups

1            In the DataCore Servers Panel, right-click on a virtual disk and point to Add to Group and then select Create Group.

2           The Create Virtual Disk Group dialog box opens. A default name is entered in the name field. Change the default group name and enter a description of the group if necessary.

3           From the list, select one or more virtual disks to add to the group.  

4          Click Create.

After the group is created:

o           The virtual disk group appears in everywhere that individual virtual disks appear in the management console.

o           Virtual disk group actions are initiated in the same manner as other individual virtual disk actions.

o           A Virtual Disk Group details page is created for the group.

Adding Virtual Disks to Existing Groups

In the DataCore Servers Panel, Host Panel or any virtual disk list, right-click on a virtual disk and point to Add to Group and then select the group.

If the virtual disk has snapshots or rollbacks, the snapshots and rollbacks will not be added to the group, only the virtual disk is added.

Serving Groups to a Host

Virtual disk groups can be served to hosts. The same wizard is used to serve virtual disks and virtual disk groups. Instead of selecting individual virtual disks, one or more virtual disk groups can be selected. Individual virtual disks from the group can also be selected and served. When serving multiple virtual disks in a group, a starting LUN can be selected and that number will be the starting LUN value to use when serving that group of virtual disks. For detailed instructions on serving virtual disks and groups, see Serving Virtual Disks. The operation can also be initiated from the DataCore Servers Panel by right-clicking on a group and selecting Serve to Hosts.

When virtual disk groups are served, associated snapshots and rollbacks in the virtual disk group are not automatically served. They must be served individually.

Performing Snapshot Operations on Groups

Snapshots can be created for a virtual disk group in the same manner as an individual virtual disk. When a snapshot of a virtual disk group is created, the "snapshot group" will contain a snapshot of every virtual disk in the group. After a snapshot group is created, additional snapshot operations can be performed on the snapshot group. Snapshots operations are performed in the same manner and with the same rules as a snapshot operation on an individual virtual disk. See Snapshot Operations for more information.

A snapshot group is listed under the source virtual disk group wherever it appears in the management console.

Detail pages will exist for snapshot groups and all individual snapshots in the snapshot group.

 Important:

o           A mapstore pool is required to be set for all applicable DataCore Servers that are a storage source of virtual disks in the group.

o           When a snapshot group exists, all subsequent snapshot operations performed on that snapshot group must be performed at the snapshot group level, not on individual snapshots in the group. Group snapshot operations cannot be performed on snapshots of virtual disk members that are not members of the snapshot group.

o           The preferred snapshot pool feature enables snapshots to be created for virtual disks in a group which do not belong to the same server. Preferred snapshot pools are assigned per virtual disk. The Create Snapshot operation will only be performed if preferred snapshot pools are set for all virtual disks in the group or preferred snapshot pools are set for virtual disks that do not belong to the server selected in the wizard.
 The best practice when using preferred snapshot pools is to set a preferred snapshot pool for all virtual disks in the group.

o           Individual snapshots in the snapshot group may be deleted.

o           When a snapshot group is split, a new virtual disk group will be created and the resulting virtual disks will be added to the new group.

o           When a snapshot group is deleted, all snapshots in the group will also be deleted.

o           When a snapshot is created for a virtual disk group and a failure occurs that prohibits the creation of all snapshots for the group, then no snapshots will be created.

o           Also see Shared Multi-port Array Support for information about dual virtual disks.

Performing Rollback Operations on Groups

Continuous Data Protection (CDP) can be enabled for a virtual disk group and rollbacks can be created for the group.  When a rollback is created for a virtual disk group, the "rollback group"  will contain a rollback of every virtual disk in the group that has data protection enabled. After a rollback group is created, additional rollback operations can be performed on the rollback group. Rollback group operations are performed in the same manner and with the same rules as a rollback operation on an individual virtual disk. See Continuous Data Protection Operations for more information.

A rollback group is listed under the source virtual disk group wherever it appears in the management console.

Detail pages will exist for every rollback group and all individual rollbacks in the rollback group.

 Important:

o           Enabling and disabling CDP can be performed on the group or individually on members of a virtual disk group. In order to enable CDP at the group level, all group members must be eligible for CDP and not already have CDP enabled; otherwise, members must be enabled individually. See Continuous Data Protection Operations  for eligibility requirements. If the group members are comprised of storage sources that do not have a common server, CDP will have to be enabled at the server level for each affected server.

o           Disabling CDP at the group level will disable all eligible group members on all servers. CDP cannot be disabled at the group level unless all group members are healthy.

o           When a rollback group is created, the earliest restore point for the virtual disk group will be the latest time any member of the group was enabled for CDP.  

o           The Create Rollback operation will only be performed on applicable virtual disks in the group. Rollbacks are only created for those virtual disks that have CDP enabled for the same server that is selected when the rollback group is created.
For example, assume that a rollback group is created for VD Group 1 with ServerA selected. Rollbacks will not be created for any virtual disks in the group that have a different server selected for CDP.

o           When a rollback group exists, all subsequent rollback operations performed on that rollback group must be performed at the rollback group level, not on individual rollbacks in the rollback group. Group rollback operations cannot be performed on existing rollbacks of virtual disk members that are not members of a rollback group.

o           Individual rollbacks in the rollback group may be deleted.

o           When a rollback group is split, a new virtual disk group will be created and the resulting virtual disks will be added to the new group.

o           When a rollback group is deleted, all rollbacks in the group will also be deleted.

o           When a rollback is created for a virtual disk group and a failure occurs that prohibits the creation of all rollbacks for the group, then no rollbacks will be created.

Performing Replication Operations on Groups

When replications are created for virtual disks in a group, additional replication operations can be performed at the virtual disk group level. Operations include activating or deactivating virtual disks, pausing or resuming transfers, marking checkpoints, and splitting replications. Replication operations are performed in the same manner and with the same rules as a replication operation on an individual virtual disk. See Replication Operations for more information. Replication operations can also be performed individually on virtual disk group members.

 Important:

o           When replication commands are invoked on a virtual disk group, replication operations will only be performed on virtual disk group members that are configured in replications and in a state that allows the operation to be performed. These conditions may not apply to all virtual disks in the group.

o           Replication checkpoints cannot be sent to a group.

Enabling/Disabling Sequential Storage on Groups

Enabling and disabling sequential storage can be performed on the group or individually on members of a virtual disk group.

Notes:

o           In order to enable the feature at the group level, all group members must be eligible for sequential storage and not have the feature already enabled; otherwise,members must be enabled individually. See Sequential Storage for eligibility requirements.

o           In order to disable the feature at the group level, all group members must be healthy and all affected servers must be running. Disabling sequential storage at the group level will disable the feature for all eligible members in the group and skip members that are already disabled.

Renaming Groups and Virtual Disks in Groups

Also see Rules for Naming SAN Components for size limitations.

Renaming Groups

Virtual disk groups, snapshot groups, and rollback groups can be renamed using either method:

o           From the DataCore Servers Panel or Hosts Panel, right-click on the object and select Rename. Enter the new name.

o           From the details page for the object, click Edit at the top of the page. Enter the new name and click Done. Tip

Renaming Virtual Disks in Groups

Virtual disks that are members of virtual disk groups, snapshot groups or rollback groups can be renamed in one operation. All virtual disks that are members of the group will be renamed based on the root name provided. Numbers are appended to the root name when multiple virtual disks exist in the group.45768

 Important:

o           This operation does not change the name of the group; only group members.

o           If the operation is performed from a virtual disk group, the operation will only be performed on virtual disks in the group, not members of subgroups.

o           To change the name of snapshots or rollbacks in a group, the operation must be invoked from the snapshot or rollback group.

To rename a group:

1            In the DataCore Servers Panel, Host Panel or Virtual Disks List, right-click on the group to rename and select Rename Virtual Disks. A box will appear.

2           In the box, enter the new root name for the group.

Removing Virtual Disks from Groups

Virtual disks can be removed from virtual disk groups, snapshot groups and rollback groups.

 Important:

o           When a virtual disk is removed from a virtual disk group, associated snapshots and rollbacks are removed from the subgroups and will be listed under the virtual disk that was removed from the group.

o           When a snapshot or rollback is removed from a snapshot or rollback group, the snapshot or rollback will be removed from the subgroup and will be listed under the source virtual disk in the group. The removed snapshot or rollback is no longer a part of the group, cannot have subsequent group actions performed on it and cannot be added back to the group.

In the DataCore Servers Panel, Host Panel or Virtual Disks List, right-click on a virtual disk and select Remove from Group.

Deleting Groups

Virtual disk groups, snapshot groups, and rollback groups can be deleted.

 Important:

o           When a virtual disk group is deleted, any snapshot groups or rollback groups in the virtual disk group will also be deleted. This operation will cause the permanent destruction of the associated snapshot and rollbacks in the virtual disk group. The virtual disks that are members of the virtual disk group are not deleted; they are only removed from the group.

o           Deleting snapshot groups and rollback groups will result in the permanent destruction of the associated snapshot and rollbacks in the group.

To delete a group:

1            In the DataCore Servers Panel or any virtual disk list, right-click on a group and select Delete.

2           A confirmation message appears; read the message carefully. To continue with the operation, click the check box, then click Yes.

Viewing Group Details

Each virtual disk group has a details page with pertinent information for that group.

Group name and  description can be changed at the top of the page by clicking Edit. When changes are made, click Done.

To open the details page for a virtual disk group:

1            In DataCore Servers Panel or Hosts Panel, expand Virtual Disks and click the group. Tip

2           Information is organized under tabs (described below). Click on a tab to view the information. Additional fields may be available by selecting Column Chooser from the column header context menu in tabs.

When the Virtual Disk Group Details page  is active, the Virtual Disk Group Actions tab appears in the Ribbon to perform actions on the group.