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Description

This article describes how to create a DRS Consistency Group. Consistency Groups are the core construct of the DRS for Cloud service and consist of a series of "paired" Cloud Servers. Cloud Servers are added to Consistency Groups in pairs - one "source" server and one "target" server. All of the Source Servers must be in the same location and all of the Target Servers must be in the same location.

For more information on Consistency Groups, see Introduction to DRS for Cloud

Important Note

Unlike most CloudControl functions, only Primary Administrators or sub-administrators with the DRS role will even see the DRS for Cloud menu that is needed to view and manage the DRS for Cloud functions. Ensure your users have the proper roles assigned - see How to Manage the Primary Administrator User and other Sub-Administrators as the Primary Administrator

Note that even when the roles are assigned, the menu appears only where the feature is available

Prerequisites:

  1. Only the Primary Administrator or a user with the DRS role can create a Consistency Group
    1. For instructions on how to add Roles to a Sub-Administrator, see How to Manage the Primary Administrator User and other Sub-Administrators as the Primary Administrator
  2. All proposed Source Server(s) must be in the same MCP 2.0 Network Domain or MCP 1.0 Network (note this implies the same location)
  3. All proposed Target Server(s) must be in the same MCP 2.0 Network Domain or MCP 1.0 Network (note this implies the same location)
  4. Both the Source and Target Locations (implied from the MCP 2.0 Network Domain or MCP 1.0 Network above) are:
    • In different Locations 
    • Not in Hypervisor maintenance
    • Not in DRS maintenance
    • Enabled for the vendor for DRS
  5. The Target Location must be an available Target for the Source Location
  6. All proposed Source Server(s) must be running
  7. All proposed Target Server(s) must be DRS eligible – see How to Manage DRS Eligibility of a Cloud Server for more information
  8. Journal Size must be within the range supported in both the Source and Target Locations
  9. Target Server(s) must match their paired Source Server(s) in terms of the following parameters:
    1. Target Servers must have the same number of SCSI, IDE, SATA, and Floppy Controllers in the same Bus ID as those on the paired Source Server
      1. In addition, for SCSI Controllers, the "adapter" type (BUS_LOGIC, LSI_LOGIC_PARALLEL, etc) on each controller must also match
    2. All of the Target Server local disks must be the same Size and be placed in the SCSI/SATA/IDE Controller and position as the paired Source Server
      1. However, the Disk Speeds on the Target Server do NOT need to match Source Server
    3. NIC Configuration
    4. NIC Key/NIC ID - To identify the NIC Key/NIC ID, see: Navigating the Server Dashboard
    5. Network Adapter - See: How to Change the Network Adapter of a NIC on a Cloud Server
  10. It is NOT required that Target Servers match their Source servers in terms of the following parameters:
    1. The same CD-ROM devices do not need to exist in the same slots on any IDE/SATA controller of the Target Server as exist on the paired Source Server
    2. ISO files do not need to exist on any CD-ROM of the Target Server to match what exists on the Source Server
    3. FLP files do not need to exist on any Floppy Drive of the Target Server to match what exists on the Source Server
  11. IMPORTANT NOTE - REPLICATION LIMITATIONS RELATED TO CD-ROM AND FLOPPY:
    1. CD-ROM devices and any attached ISO are NOT replicated. Any devices or ISO on the Target Server remain unchanged after Failover.
      1. It does not matter if these devices exist in matching slots in the Target Server
    2. Floppy controllers and any attached FLP are NOT replicated. Any FLP on the Target Server remain unchanged after Failover
      1. It does not matter if these devices exist in matching slots in the Target Server
  12. You can not create a Consistency Group if the Cloud Server Snapshot Feature is enabled on the Target Server. See How to Disable Cloud Server Snapshots on a Server
    1. However, you CAN create a Consistency Group if the Cloud Server Snapshot Feature is enabled on the Source Server.
  13. A Server cannot be a Source Server or a Target Server if it is in Snapshot Preview. You must first migrate the Snapshot Preview Server to a Normal Server. See Introduction to Cloud Server Snapshot Feature
  14. You cannot create a Consistency Group if one (or more) of the Servers are in a state which requires it to be restarted. See the "Adding and Managing Disks" section of Introduction to Cloud Server Local Storage ("Disks") and Disk Speeds
  15. DRS Journal Size must be between 100 GB and the lesser of the maxSizeGb in the Source and Target Location
    1. Sizes must be specified in 100 GB increments
  16. In order to create a DRS Consistency Group, the Target Server(s) must NOT have any of the following Advanced Virtualization Settings:
    1. Nested Hardware Virtualization set to true,
    2. CPU Latency Sensitivity set to HIGH
    3. Numa Autosize set to true
    4. Enable Host Info to VM Tools set to true
      1. Note: It does NOT matter what Advanced Virtualization Settings are on the Source Server. None of them are copied onto the Target.
      2. Note: For more information on Advanced Virtualization Settings, see Introduction to Advanced Virtualization Settings

Content / Solution:

  1.  Click on the DRS for Cloud menu button and then select DRS Consistency Groups to navigate to the DRS Consistency Groups page:
     


  2. The DRS Consistency Groups dashboard will be displayed:

    Note: If there are no Consistency Groups defined, the dashboard will display the following message: No records available.

  3. Click on the Add Consistency Group button:


  4. The Add Consistency Group dialog will be displayed:

     

  5. Fill out the form with the appropriate information:

    • Consistency Group Name - Enter a unique name for the Consistency Group. 
      • Note: Name must be 75 characters or less
    • Consistency Group DescriptionEnter an optional description of the Consistency Group. 
      • Note: Description must be 255 characters or less
    • Initial Journal Size Select the desired size of the Journal datastore in 100 GB increments.  This datastore will be used to hold the incremental DRS snapshots created for the Consistency Group.

    • Source Location Network Domain - Select the Network Domain in which the Source Server resides from the drop-down:
    • Target Location Network DomainSelect the Network Domain in which the Target Server resides from the drop-down:
    • Add Server Pair - Click the Add Server Pair button to add a Source Server and its corresponding Target Server to the Consistency Group
      • Note: You will need to click the Add Server Pair button every time you want to add a new Source and Target server pair to the Consistency Group
      • Note: A maximum of 10 server pairs can be added to a Consistency Group 
    • Source Server - The server within a Consistency Group's server pair that is the "source" of replication
      • You can search for all available Source Servers within the specified Source Location by typing the Server Name or IPv4 address of the server's Primary NIC into the appropriate field
      • Only one server can be specified as the 'source' of a corresponding Target Server
      • Servers that are already in a Consistency Group will not be available for selection 
    • Target Server - The server within a Consistency Group's server pair that is the "target" of replication
      • You can search for all available Target Servers (i.e. servers flagged as 'DRS Eligible') within the specified Target Location by typing the Server Name or IPv4 address of the server's Primary NIC into the appropriate field
      • Only one server can be specified as the 'target' of a corresponding Source Server
      • Only servers that have been flagged as 'DRS Eligible' will be available for selection as Target Servers.  See How to Manage DRS Eligibility of a Cloud Server for more information. 
      • Only servers on clusters that can support the number of vCPUs and amount of RAM of the specified Source Server will be available for selection as Target Servers
      • Servers that are already in a Consistency Group will not be available for selection
       
  6. Once the form has been filled out, click Save:

    Note: Hovering your mouse over the  information icon will display a popup which indicates the valid Journal Size range:


  7. The system will display a message indicating that the operation is in progress:


  8. The system will indicate the progress of the operation in the DRS Consistency Groups table:


  9. The system will display a success message:


  10. The Consistency Group will be created and the UI will be updated to reflect the change:


State of Target Servers after Consistency Group Creation

NOTE: Upon creation of the Consistency Group, each Target Server will be reconfigured to 1 CPU and 1 GB RAM and will match its paired Source Server in terms of Cores per Socket and OS Type; its CPU Speed will be set to the ‘default’ CPU speed for the Target Server’s data center location; Priced Software will be removed (if applicable); and it will be powered on.

Prohibited Functions of Source and Target Servers

When Source Servers and Target Servers are added to a Consistency Group, several server management functions are disabled in order to preserve the integrity of the DRS for Cloud service.  Please see the following articles for more information:

Important Note: After a Consistency Group has been created, the Target Server(s) will appear to not have VMware Tools installed, even if VMware Tools is on the Source Server or if it was installed prior to making it a Target Server. The correct status will appear when the Target Server is "activated" as part of a Snapshot Preview.

Important Note: If for some reason the Consistency Group deployment fails, you will need to open a ticket with support to have it cleaned. See How do I Gain Access to Support Resources