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Creating and managing Replication in Unisphere is easy and intuitive. All replication operations, including configuring of replication network interfaces, replication connections, and replication sessions can be performed in the Unisphere GUI. With the help of easy to follow wizards, replication can be configured quickly by IT generalists or advanced users alike. Replication can also be configured using Unisphere CLI, or REST API. For more information about configuring and managing replication using Unisphere CLI, refer to the Unisphere Command Line Interface Guide found on Dell Online Support. For more information about REST API, refer to the Unisphere Management REST API Programmer’s Guide found on Dell Online Support.
When configuring remote asynchronous replication, the following components need to be configured and were previously discussed in the paper:
Note: When configuring local replication between Pools on a system, Replication Interfaces and a Replication Connection do not need to be configured on the system.
The following sections will outline the remaining steps needed to configure remote replication in Unisphere. Each of the following operations is completed from a particular page in Unisphere. Each page will be discussed in detail below. For more information about using Unisphere to configure and manage replication, refer to Unisphere Online Help.
Mobility Interfaces may be shared network interfaces for import and replication-related data or management traffic using the virtual management port. In this section, the mobility interfaces will be referenced as replication interfaces. To create replication interfaces, you must first go to the Interfaces page, which is found under Protection & Mobility in the left pane in Unisphere. Creating replication interfaces is completed on the Interfaces page. For releases prior to Dell UnityOS version 4.1, the Interfaces can be found as a tab in the Replication page, under Data Protection in the left pane.
Figure 42 below shows the Unisphere Interfaces page. From this page, you have the option to create or delete replication interfaces, refresh the current page, or edit a configured replication interface. In the example below, no replication interfaces have been created. One or more pairs of replication interfaces need to be created on the source and destination system to configure remote replication.
Figure 42. Interfaces page
To create a replication interface for remote replication, click the Create Interface button, shown as a + sign in the Interfaces page. Once selected, the Create Interface wizard appears, which is shown on the left in Figure 43. For remote replication, you must create replication interfaces on the system, which are used for connectivity between the source and destination system. In the Ethernet Port drop down list, select an available port. The status of the ports will be shown in parentheses. Both ports on each SP will need to be cabled to the network for these links to work properly. Figure 43 also shows an example of the Ethernet Port drop down choices on a physical system. All Ethernet ports are available to create a network interface. Also shown are Link Aggregation ports previously created on the system.
Next, configure an IP address for SPA and SPB to be used for the replication interfaces. Once done, click OK.
Figure 43. Create Interface window
Once the replication interfaces are created, they will be shown on the Interfaces page as shown in Figure 44. From here the status of each port is shown, currently operating normally as denoted by the green circle checkmark. To delete a replication interface, select the port and click the Delete Interface icon, which is shown as a trash can on this tab. To edit a replication interface, to change the IP address for example, select the Edit icon, which is shown as a pencil icon on this tab.
Figure 44. Configured replication interfaces
Figure 44 above is also an example of a replication configuration leveraging the asynchronous replication interface pairing enhancements introduced in Dell UnityOS version 5.1. This feature is described in detail in section 0 Replication Interfaces. In this example, multiple replication interfaces using different VLAN IDs have been created on the same front-end ports. A pair of these ports on VLAN 1001 will connect to one remote system, while the ports configured with VLAN 1002 will connect to a different system. The interfaces created on 4-Port Card Ethernet Port 1 on both SPs will be used to connect to a third system over a different physical port and network.
The next step in configuring remote replication is to create a Replication Connection with another system. This configures a private replication connection for the pair of systems. On the Replication page, multiple tabs exist, including Sessions and Connections. From the Replication page, select the Connections tab. Figure 45 below shows an example of the Connections tab without any replication connections configured. From this tab, you have the option to create or delete a replication connection, refresh the current page, or edit a configured replication connection. From this tab, you can also select Verify and Update, which will verify the selected replication connection still exists with the remote system and update the connection details if any changes were made.
Figure 45. Replication Connections
To create a Replication Connection for remote replication, select the Create Replication Connection icon, which is displayed as a + sign on this tab. The Create Replication Connection window appears, as shown in Figure 46. On the System Settings step, you must specify the Remote System’s Management IP Address, which is the IP used to access Unisphere, and the Unisphere User Name and Password. Also, in this window you must enter the Password used to log in to Unisphere on the system you are configuring the replication connection in. Lastly, you must select the Connection Mode that will be used between the systems. In the drop-down list, you have the option to choose Asynchronous, Synchronous, or Both. When configuring asynchronous replication between two systems, select Asynchronous. If synchronous and asynchronous replication will be used, select Both. After entering the required information, click Next. The Bandwidth Schedules step is then shown. This feature was discussed in section 0 Asynchronous replication throttling.
Figure 46. Create Replication Connection window
After completing the System Settings and Bandwidth Schedules steps and clicking OK on the Summary step, a Job is created to create the replication connection. The job has multiple steps, which include registering the remote and local system with its peer, refreshing the connection on both systems, and validating the connections on the local system. Once the job completes, the replication connection will be shown on the source and destination system.
Figure 47 shows the Replication page Connections tab once the replication connection is created. In this example, the name of the remote system is displayed. The System Type, Management IP Address, Replication Mode, and Remote Interfaces are also displayed. The Remote Interfaces displayed will be the IPs for the synchronous replication management ports and asynchronous replication interfaces on the remote system.
Figure 47. Replication Connections
To create a replication session, you must enable replication on the storage resource you want to replicate. This can be done at time of creation, or on an existing storage resource. Figure 48 shows an example of creating a new LUN and enabling asynchronous remote replication on it. From the Replication step, check the checkbox in front of Enable Replication to configure replication. For asynchronous replication, select Asynchronous from the Replication Mode drop-down box and customize the RPO as needed. Choose Manual to create a manual replication session. When asynchronous is chosen as the Replication Mode, the Replicate To box will automatically be populated with a remote system name asynchronous replication can be configured with. If you want to replicate locally with asynchronous or manual replication, choose Local found under Replicate To. The Replicate scheduled snapshots option is also shown and allows the replication of scheduled snapshots. The retention policy for snapshots on the destination can also be customized. After completing this step, click Next and continue with the creation. For LUNs, consistency groups, VMware VMFS datastores, thin clones, file systems, and VMware NFS datastores, a Replication step exists in the creation wizards for each with the similar look and configuration options as the one shown in Figure 48.
Figure 48. Enable Asynchronous Replication
When the Destination Configuration box is selected in the Replication step, information about the remote storage resource’s configuration will be displayed. Depending on the capabilities of the remote system, the destination Pool, and the resource type, options for Thin and Data Reduction will be displayed. The Reuse destination resource option allows for recreating a replication session to an existing resource on the destination. Figure 49 below shows an example of this window.
Figure 49. Destination LUN Configuration window
After asynchronous replication is configured on a new storage resource, you can view information about replication from the resource’s properties window. From Unisphere, select the storage resource in question and click Edit or double-click the name of the storage resource. From the properties window, view the Replication tab. An example of this tab for a LUN is shown in Figure 50. On this tab, you can view the following information:
Also shown is a pictorial representation of the replication session. The figure shows which storage resource is available for I/O, which direction the data is replicating in and its current state, and the destination storage resource and the system name, IP Address, and the destination LUN name. As the state of the replication session changes, this figure will update to reflect the new state.
Also shown on the Replication tab are buttons for each Replication Operation. This tab is also used to display synchronous replication operations, so all replication operations for synchronous and asynchronous replication are displayed. Not all replication operations are supported on each mode of replication, so only operations supported on the current replication mode will be selectable. Also, only certain operations are available depending on what the current state of the replication session is in, so only these options are available for selection. In Figure 50, the current session is Auto Sync Configured and replicating from the Production System (Local System) to the DR System. Available replication operations for the asynchronously replicated LUN include Delete, Pause, Sync, and Failover with Sync.
Figure 50. LUN replication configured
Replication can also be configured on an existing storage resource. When replication is not configured on the storage resource, viewing the Replication tab in the storage resource’s properties window will show what is displayed in Figure 51. The Replication tab for a consistency group, VMware VMFS datastore, thin clone, file system, and VMware NFS datastore displays the same information below. To configure Replication on the storage resource, select Configure Replication.
Figure 51. Replication not configured
After selecting Configure Replication, the Create a Session wizard is launched. An example of this wizard is shown in Figure 52. On the Replication Settings step, you need to customize which Replication Mode either Asynchronous, Manual, or Synchronous replication will be used. For Asynchronous Replication, select Asynchronous. Next, customize the wanted RPO if needed. When manual replication is selected, RPO will not be an option. Then, select the destination system by selecting the correct system in the Replicate To drop down box, either Local for local replication, or a listed remote system. As mentioned previously, Dell UnityOS version 4.2 supports the replication of scheduled and user snapshots. The Replicate all existing snapshots is a one-time option, given at creation time of the replication session, that can be used to replicate all existing snapshots. The Replicate scheduled snapshots option can be used to replicate the scheduled snapshots of a storage resource, this option can be modified after the replication session creation. Figure 52 shows both options already selected. The Reuse destination resource, Automatically search user snap as common base, and Overwrite Destination options will be discussed in detail in section 0 Common Base Snapshots.
Figure 52. Create a Session wizard – Replication Settings step
In the example in Figure 52, the LUN has both Hourly and Daily/Weekly snapshot schedules. To customize the remote retention policy for the snapshots that will be replicated, click the Customize button, which opens the Customize Remote Retention window. An example of this window is shown in Figure 53. This provides the options to either keep the same retention policy as the source, follow the Pool Automatic Deletion Policy, or retain the snapshots for a custom number of hours, days, or weeks. The retention policy can go up to 255 weeks. In this example, Hourly Snapshots are retained for seven Hours while the Daily/Weekly Snapshots are retained for four Weeks. After selecting the retention policy, click OK, and then Next.
Figure 53. Customize Remote Retention
The Destination step of the Create a Session wizard is now shown. An example of this step for a LUN is shown in Figure 54. From here, you can customize the storage resource’s Name that will be displayed on the destination Pool or system, the Pool it will use, the Storage Processor if applicable, the Tiering Policy if applicable on the destination’s Pool, and enable Data Reduction/Advanced Deduplication if supported on the resource and the destination. For other existing storage resources being replicated, you can customize this exact same information. When creating a replication session on an existing consistency group, you can customize this same information for each LUN contained within the consistency group. After editing the available information, click Next.
Figure 54. Create a Session wizard – Destination step
The Summary step is next in the Create a Session wizard. Here you can see a summary of the settings that will be used to create replication. If anything is incorrect, you can select Back to correct the wanted setting. To create the replication session, click Finish. A Summary step will also be shown when creating a replication session on other storage resources.
The Results step is the last step in the wizard. This step shows the Overall Status of each of the jobs to create the replication session. The steps to create the replication session include creating the storage resource on the destination system, allowing the remote storage resource to finish the creation process, and lastly creating the replication session. You can either wait for the Overall status to say 100% Complete or close the window at any time by clicking Close. Closing this window will not impact the creation process since it is a background job in Unisphere.
As mentioned previously, advanced File replication topologies allows File resources to be replicated asynchronously or synchronously in fan-out and cascade topologies, as discussed in section 0. Each replication session within an advanced replication topology is created separately. Before file systems or VMware NFS datastores can be replicated, the NAS Server must first be replicated to the desired destination Pool or remote system. The replication session for the NAS Server can be established when the NAS Server is created, or on an existing resource. Figure 55 shows an example of creating a new NAS Server and enabling Asynchronous remote replication on it.
From the Replication step, check the checkbox in front of Enable Asynchronous Replication to configure replication. For asynchronous replication, select asynchronous from the Replication Mode drop-down box and customize the RPO as needed. Choose Manual to create a manual replication session. When asynchronous is chosen as the Replication Mode, the Replicate To box will automatically be populated with a remote system name asynchronous replication can be configured with. If you want to replicate locally with asynchronous or manual replication, choose Local found under Replicate To.
Figure 55. Enable Asynchronous Replication
When the Destination Configuration link is selected in the Replication step, information about the remote storage resource’s configuration will be displayed. The Reuse destination resource option allows for recreating a replication session to an existing resource on the destination. Figure 56 below shows an example of this window. After updating this window as needed, click OK and then Next to continue with the NAS Server creation.
Figure 56. Destination NAS Server Configuration window
After asynchronous replication is configured on the NAS Server, you can view information about replication from the resource’s properties window. From Unisphere, select the storage resource in question and click Edit or double-click the name of the storage resource. From the properties window, view the Replication tab. An example of this tab for a NAS Server is shown in Figure 57. As File resources can have multiple replication session, they are all shown on this tab. In this example the NAS Server has been replicated in a fan-out configuration to three destination systems. On this tab, you can view the following information:
Figure 57. NAS Server replication configured
Replication actions, such as Pause, Resume, and Failover, can be issued from the Replication tab. After selecting a replication session in the list, click More Actions. The options available depends directly on the replication state of the resource. The properties of each replication session provides more information to the user. To view information about a replication session, double click the session name or select the session and click the View/Edit icon.
A pictorial representation of the replication session is shown in the properties of the session, as seen in Figure 58. On this screen the Session Name, Mode, and Time of Last Sync is displayed. The figure also shows which storage resource is available for I/O, which direction the data is replicating in and its current state, and the destination storage resource and the system name, IP Address, and the destination LUN name. As the state of the replication session changes, this figure will update to reflect the new state.
Figure 58. Replication session properties
When replication is configured on an existing NAS Server, all resources on that NAS Server are also replicated. A replication session can be deleted from a resource that should not be replicated at any time. When a new resource is added to a replicated NAS Server, the Replication step allows the new resource to be created with the same replication topology as the NAS Server. Figure 59 shows the Create a File System wizard. In this example, the parent NAS Server is replicated to three remote systems. On the Replication step, replication on the new file system can also be configured. A checkbox, disabled by default, is specified for each destination. When a checkbox is selected, the replication session will be created with the same attributed as the associated NAS Server session.
Figure 59. Replication not configured
To customize a replication session to a specific destination, select the Destination Configuration link for the corresponding session. In the Replication details Configuration screen, as seen in Figure 60, many options can be customized. These options include the Replication Mode, either Asynchronous or Manual, the RPO, the destination Pool, the Tiering Policy, and the Snapshot Replication Configuration. These options can be independently configured on each replication session. The Reuse destination resource option will be discussed in detail in section 0 Common Base Snapshots.
Figure 60. Create a Session
On the Summary step of the Create a File System wizard, all configuration information for the resource is displayed. As with other resources, if a correction needs to be made, the Back button can be used. Each replication session being created is shown on the Summary screen, as seen in Figure 61. The Replication Mode, RPO, and Destination System are shown. To view more information about a specific session, click the More Info link under Session Details.
Figure 61. Create a File System – Summary step
When More Info is selected, the Replication details Configuration window is shown. If any settings for the replication session need to be changed, simply close this window and click the Back button.
Figure 62. Replication details Configuration window
Once the resource is created, replication information can be seen on the Replication tab within the properties of the resource. As with NAS Servers, the replication tab for file systems and NFS datastores will display all replication sessions currently configured on the resource. An example of this screen can be seen below. Replication operations, such as Pause, Resume, and Failover can be found under More Actions. To view more information about a specific replication session, simply select the session and click the View/Edit icon.
Figure 63. File system properties – Replication tab
A pictorial representation of the replication session is shown in the properties of the session, as seen in Figure 64. On this screen the Session Name, Mode, and Time of Last Sync is displayed. The snapshot replication settings are also displayed. The figure also shows which storage resource is available for I/O, which direction the data is replicating in and its current state, and the destination storage resource and the system name, IP Address, and the destination LUN name. As the state of the replication session changes, this figure will update to reflect the new state.
Figure 64. Replication session properties screen
Once the source snapshots have been replicated to the destination, the source snapshot can be deleted from the source system to free up space. If there is ever a need to recover data that is in a replicated snapshot, the replicated data can be manually restored to the source storage resource. Taking a backup of the source resource is suggested, as this process will overwrite data within the source resource. To manually restore from a replicated snapshot, once the snapshot has been replicated, failover the storage resource’s replication session, and on the destination system, restore the storage resource to the snapshot that has the data you are interested in. Once the restore is complete, failback the replication session. As result, the source storage resource will contain the data that was on the snapshot.
If you have file replication configured with a destination site on a different physical network, to ensure minimal downtime during a failover, ensure that you modify the destination NAS Server properties to include an override address for the network interface. Figure 65 shows an example of the destination NAS Server with the Production Interface being overridden to a different IP Address. A different Ethernet Port can also be selected in this process.
Figure 65. Override address
Dell Unity supports 3-way NDMP (Network Data Management Protocol) backup over Ethernet. Also, as of Dell UnityOS version 4.4, 2-way NDMP backup over Fibre Channel is also supported. This support allows for data backup to NDMP backup clients which could be a tape library or virtual tape appliance. NDMP can also work in cohesion with replication for additional data protection. If replication is enabled on a NAS Server and additional data protection is needed, NDMP can be enabled through the Protection & Events tab in the properties page of a NAS Server, as seen in Figure 66. NDMP can be enabled either on the source or destination NAS Server giving configuration flexibility in running incremental NDMP backups of file systems. If you enable NDMP on a destination NAS Server, you will first need to create a Backup & DR testing network interface to be able to connect to destination file resources. Also note that enabling NDMP for the destination NAS Server is not supported in the initial UnityOS 4.0 release but is supported in UnityOS 4.1 and later.
Figure 66. Enable NDMP
All replication sessions on the system can be viewed from the Sessions tab within the Replication page. This includes synchronous and asynchronous replication sessions. To go to this page, click Replication under Protection & Mobility in Unisphere. For releases prior to Dell UnityOS version 4.1, the Replication page can be found under Data Protection. Figure 67 shows an example of the Sessions tab with multiple replication sessions created on the system. In this example, you can see replication sessions for the TEST NAS Server and TESTFS file system created in the Advanced File Remote Replication section. In this example, the NAS Server and file system are configured in an asynchronous replication fan-out topology, replicating to three destination systems. From this page, you can easily see information regarding each session. The following is a list of information displayed on this screen. More columns can be added to the view if needed.
Figure 67. Replication Sessions
From the Sessions tab, you can also issue replication operations on the sessions. After selecting the checkbox for a replication session in the list, select More Actions to view the replication operations available for that session in its current state. In Figure 68 below, you can see that only Pause, Sync, and Failover with Sync are valid options based on the current replication session state of the selected storage resource.
Figure 68. Replication Sessions – More Actions
Dell UnityOS version 4.2 also includes the group operations feature at a NAS Server level. The group operations are available for the following operations: Failover, Failover with Sync, Failback, Pause, and Resume. Figure 69 gives an example of performing a group Failover for a NAS Server.
Figure 69. Failover with sync