Configuring EMC Unity Replication

Following on from the EMC Unity Setup Guide and EMC Unity Configuration Guide, we will walk through setting up replication between 2 Unity arrays. For Remote Office and Branch Offices replication can be configured between the Unity VSA and a physical Unity array in the datacentre.

Replication between storage devices provides data redundancy and protects against storage system failures. EMC Unity provides synchronous or asynchronous replication; synchronous replication is only available to physical arrays and can protect LUNs, Consistency Groups, and VMware VMFS datastores. Asynchronous replication is applicable to all products in the Unity range and can protect the storage resources listed previously, as well as File Systems, NAS Servers, and VMware NFS datastores. Replication can be configured within the same system or to a different system locally, or in a remote location. All EMC Unity systems are licensed for replication as standard. For more information on EMC Unity replication technologies see the Unity Replication White Paper.

Establishing Replication Connections

Before configuring replication a secure link between Unity systems must be established. All tasks are carried out using the HTML5 Unisphere web client. Browse to the IP or FQDN of either Unity system.


Under Data Protection on the left hand navigation pane select Replication. First we need to configure the interfaces to use for replication traffic, so click the Interfaces tab.


Click the plus symbol (Create Replication Interface). Select the interface to use on each storage processor, if you have created link aggregation groups these are also listed. For assistance with creating link aggregation groups see the EMC Unity Configuration Guide. Enter the IP address to use for replication traffic for each storage processor, configure a VLAN ID if required, and click Ok.


The created replication interfaces will now be listed, you can also edit and delete replication interfaces from this tab. You need to configure the replication interfaces on both the source and destination system.

Next we setup a remote connection between the storage systems. From either device select the Connections tab.


Enter the management IP address and credentials of the remote system, and the admin password for the local system. Select the replication type; in this example we will use Asynchronous. Click Ok.


A replication connection will now be established on both the local and remote systems. Once complete click Close.

Configuring Replication

Select the storage resource to configure replication, in this post we will replicate a file system. The NAS Server hosting the file system must be configured for replication. Browse to File under the Storage menu, open the NAS Servers tab and select the NAS server to replicate. Click Edit and select the Replication tab.


Select the replication mode and RPO (Recovery Point Objective) time. The replication destination is the remote system connection we established earlier. Click Next.


Select the storage pool and storage processor for the destination storage system, the NAS Server name will auto-populate. Any existing file systems stored on the NAS Server will be listed for replication. Click Next.


Review the summary page and click Finish and Close.


When creating new file systems they can be configured for replication on the Replication page of the create a file system wizard.


A destination file system is automatically created on the destination storage system.


Alternatively we can configure replication at a later date. To do this open the File Systems tab and select the file system to replicate, click Edit.


Select the Replication tab. Click Configure Replication.


The replication wizard will open. The replication session inherits the configuration from the NAS Server. Click Next.


A file system on the destination file system will automatically be created. Select the storage pool to use on the destination storage system, click Next.


Review the summary page and click Finish. The replication session will be established, once complete click Close.


We can confirm the replication status by going back into the properties of the file system and the Replication tab where the replication status will be displayed. The replication role of the file system on the source storage system is Source, on the remote system the file system role is Destination. We can also go back to the Replication page and open Sessions. The replication sessions will be listed.


Configuring VVOLs with EMC Unity

This post will walk through the setup of VMware VVOLs with EMC Unity. If you are unfamiliar with the concept of Virtual Volumes then see this KB. You can read more about the EMC Unity physical array by reviewing the EMC Unity Setup Guide, or the Unity Virtual Appliance by reviewing the Deploying EMC Unity VSA post.

EMC Unity VVOL Components

The vStorage APIs for Storage Awareness (VASA) provider is built into the controller, so there is no additional installation or configuration required. This design also offers high availability of VVOLs which is native to the controller configuration of the Unity product line. Virtual machines are provisioned based on the VMware Storage Policy Based Management (SPBM) framework which uses the VASA client, both features are key to VVOLs and were introduced with vSphere 6.

The Unisphere interface was rebuilt when EMC introduced Unity; the first midrange EMC product to officially support VVOLs. Unity provides both NAS and SAN connectivity for VVOLs, meaning virtual volumes can be provsioined via Fibre Channel, iSCSI, or NFS. The Protocol Endpoints are the NAS Server interfaces, iSCSI initiators, and Fibre Channel ports zoned to the ESXi hosts. VVOLs reside in VVOL datastores, known as storage containers, which are made up of storage allocations from one or more capability profiles. A capability profile is built on top of one or more underlying storage pools – a storage pool can contain different disk types.



  • Before you can implement VVOLs you need to be running vSphere 6.
  • If you have already licensed vSphere for standard or above there is no additional cost.
  • At the time of writing all products in the EMC Unity range support VVOLs. If you are using an alternative storage provider cross check your hardware with VVOLs in the VMware compatibility checker, and check with your storage provider that they support VASA.
  • Check the license pack for your Unity array covers VVOLs, this will be listed in the feature table on the licensing email from EMC. If you are unsure check with your account manager.
  • The Unity 300 and 400 arrays support up to 9000 VVOLs. The Unity 500 supports 13500 VVOLs and the Unity 600 supports 30,000 VVOLs.

EMC Unity Configuration

First let’s add the vCenter Server to Unity so that ESXi hosts can be discovered. Log into the Unisphere web client and select VMware from the Access menu on the left hand side. Select vCenters and click the add symbol to add the vCenter Server. Enter the vCenter details to discover ESXi hosts that are connected via the Protocol Endpoints.


To deliver virtual volumes we need a storage pool. A storage pool was most likely configured during the setup of the Unity array. However if not, then select Pools from the Storage menu, create a storage pool using the create pool wizard.

If you already have a storage pool select VMware from the Storage menu and open the Capability Profiles tab. A capability profile is used to advertise the available characteristics of a storage pool, in this case virtual volumes. Click the add symbol to create a new capability profile. Give the profile a name and click Next.


Select the storage pool the capability profile should use and click Next.


Review the summary page and click Finish.


The capability profile will now be created.


Once complete we can go ahead and create a storage container fo virtual volumes, in EMC this is called a VVOL datastore. Select the Datastores tab and click the add symbol to create a new VMware datastore. Select VVOL and click Next.


Enter a name for the virtual volume datastore and click Next.


Select the capability profile we created earlier and click Next, multiple capability profiles can be assigned.


Configure the hosts that should have access to the virtual volume datastore and click Next.


Review the summary page and click Finish. Storage containers are now presented to the vCenter hosts specified during access configuration, these are thin provisioned by default. For further details see the official EMC Unity VVOLs White Paper.

vSphere Configuration

Since VVOLs are a new feature of vSphere 6 all configuration is done in the vSphere web client. The first task is to register the Unity VASA provider; from the home page in the vSphere web client click vCenter Inventory Lists, vCenter Servers, select the vCenter Server, click Manage and open the Storage Providers tab. Click the green add symbol to add a new VASA provider. Enter the URL of the Unity system and admin credentials, click Ok. The URL should be in the following format https:// :8443/vasa/version.xml where is the management IP address or FQDN of the Unity system.


Next we can provision VVOLs from the storage container (or VVOL datastore in EMC Unity) that we just created. From the home page in the vSphere web client click Storage, and Add Datastore. Pick the datacentre location and click Next, select VVOL as the type of datastore and click Next.


The available storage container should now be highlighted, verify the name and size, enter a name for your new datastore and click Next.


Select the hosts that require access and click Next, review the details in the final screen and click Finish. You may need to do a rescan on the hosts but at this stage we are ready to provision a new virtual machine to the virtual volume datastore with the default storage policy. This represents VVOLs in its simplest form, the virtual machine files are now thin provisioned and stored natively in the storage container we created on the Unity array. You can create additional storage based policies using the vSphere 6.0 Documentation Centre.

The release of vSphere 6.5 included VVOLs 2 built on VASA 3.0 which features support for array based replication. You can read more about what’s new here.

EMC Unity Configuration Guide

Following on from the EMC Unity Setup Guide this post will walk through the configuration of an EMC Unity array with iSCSI connectivity using the management web interface. Before beginning, ensure your Unity device is up to date by following the EMC Unity Update Guide. The EMC Unity is also available as a Virtual Storage Appliance.



The EMC Unity hybrid and all flash storage range implements an integrated architecture for block, file, and VMware VVOLs powered by the Intel E5-2600 processors. The Disk Processor Enclosure (DPE) leverages dual storage processors and full 12-Gb SAS back-end connectivity to deliver high levels of performance and efficiency. Disk Array Enclosures (DAE) are added to scale out capacity up to 3 PB top end. There is concurrent support for native NAS, iSCSI, and Fibre Channel protocols whilst the unit itself takes up less rack space than it’s competitors. Unity arrays can be managed from the HTML5 web client, or through the CloudIQ service, and offer a full range of enterprise storage features. For more information see the Unity platform white paper.

Some considerations when creating storage pools; typically we want to configure less storage pools to reduce complexity and increase flexibility. However configuring multiple storage pools may be required if you want to separate workloads for different I/O profiles or use FAST Cache. When sizing a storage pool remember that all data written to LUNs, file systems, and datastores is stored in the pool, as well as configuration information, change tracking, and snapshots. Storage pools must maintain free capacity to operate, EMC recommend at least 10%.

You will need to make design decisions based on your environment around storage pool capacities and configured RAID protection. The Unity range offers RAID 1/0, RAID 5, or RAID 6 configured at storage pool level. EMC generally recommends smaller RAID widths as providing the best performance and availability, at the cost of slightly less useable capacity, e.g. for RAID 6 use 4+2 or 6+2 instead of 10+2 or 14+2. Unity automatically reserves 1 out of every 30 drives of the same type for use as a hot spare, you can reduce the number of hot spare drives by decreasing the number of individual drive types.

Unity arrays use the first 4 drives to store configuration information and critical system data, these are known as the system drives and run from DPE Disk 0 through to DPE Disk 3. The system drives cannot be used as hot spares but can be added to storage pools in smaller configurations, if no other disks are available. The usable capacity of system drives is reduced by around 100 GB, therefore storage pools utilising system drives should use a smaller RAID width. For larger configurations with high drive counts EMC does not recommend using the system drives as heavy client workload may slow down management operations. This restriction does not apply to all-flash.

Configuration Settings

Browse to the management IP address of the Unity array configured during installation. If you have not changed the admin password the default login is admin Password123#.

The welcome dashboard gives an overview of health and capacity. Note the icons in the top right hand corner. The first symbol shows the overall system state, if there are no issues this will be a green tick. The second icon lists active jobs and the third any active alarms. Next is the settings menu, logged in user menu, and help.


Let’s start by opening the settings menu using the gear icon. The Software and Licenses page lists the licensed enabled features. To install a license click Install License and upload the .lic file provided by EMC. You can also view system limits, install language packs, software updates, and disk firmware.


The Users and Groups page can be used to add local users or an LDAP identity source.


Use the Management page to configure NTP servers and DNS. The host name and management address can also be changed here if required as well as optional services such as Unisphere Central (centralised management), remote logging, and encryption.


The Storage Configuration page allows for configuration of FAST cache; FAST cache extends existing cache using enterprise flash drives to provide instant access to frequently used data. You can also view the spare disks in the system, but it’s best to come back to this after we’ve configured our storage pool.


Configure auto-support on the Support Configuration page by entering the support credentials and contact details. Make sure you use the EMC support account where the support contract is associated.


The Access page lists the iSCSI (Ethernet) and FC ports. Double click the port to view further details, all ports should be connected and green.

For Ethernet ports it is good practise to create link aggregation where more than one port is used for the same traffic, e.g. iSCSI data, or replication. Aggregating ports together pools the resources to create a highly available configuration, iSCSI or other services then use the port aggregation group to distribute I/O and provide redundancy. Select the first port for the group and click Link Aggregation, Create Link Aggregation. You can add or remove additional ports by selecting the port and clicking Link Aggregation, and Add to Link Aggregation or Remove from Link Aggregation.


Configure email alerts, and SNMP traps if required, using the Alerts page.


Next we’ll go through the menu options in the left hand navigation pane.


The System View page lists basic system information such as the model, serial number, and software version. If any hardware issues are detected they will be listed here.


The Performance page shows IOPS and bandwidth , you can also create I/O limits.

The Service page shows a number of service related tasks and logs, as well as any technical advisories issued by EMC. Auto-support functionality should already be enabled as we configured it earlier using the Support Configuration page of the Settings menu. The support contract will auto-populate once refreshed providing the correct support settings have been entered.



The Hosts page allows for configuration of network hosts, such as Windows or Linux machines, for storage access. An individual host can be added, or a subnet or netgroup; to allow access to multiple hosts or network segments. The VMware page provides a single workflow for adding vCenter servers and ESXi host discovery. Virtual machine and VMDK information can also be imported.

For block storage resources you must register initiators using the Initiators tab. Initiators are servers initiating Fibre Channel or iSCSI sessions, and are identified by a unique World Wide Name (WWN) or iSCSI Qualified Name (IQN). The link between the initiator and the port on the storage system is called the initiator path; an initiator can be associated with multiple initiator paths. At this point for iSCSI paths to show up iSCSI interfaces must be configured on the Block page, see the Storage section above for further details. For FC paths the appropriate zoning on the FC switch must be complete for the initiator paths to be seen by the storage system.

Data Protection

The Data Protection section gives you two ways of protecting data on the array. The first is Snapshots; snapshots are used to create point in time copies of your data. There are 3 built in snapshot policies with different retention periods, or you can create your own by clicking the add symbol.

The second option is Replication, replication allows data to be copied to a different Unity array or Virtual Storage Appliance, on or off-site. To facilitate replication you must first create an interface by clicking the Interfaces tab and the add symbol. Chose an Ethernet interface, or link aggregation group, to use and configure the network settings. Next click the Connections tab and the add symbol. Enter the details of the remote Unity system to be a replication target and the connection mode; asynchronous replication, which takes an initial copy and then only updates with incremental (changed) data (recommended for most use cases) or synchronous replication, which takes full copies of the data at each replication interval. Finally configure replication on the storage resource you wish to replicate, as outlined under the Storage section below.

To configure replication see the Configuring EMC Unity Replication post.



Before using any disks in the system they must be allocated to a storage pool. When creating storage pools take into consideration the notes in the Architecture section above. To create a storage pool click Pools and the add symbol. Assign disks to the storage pool and select a RAID configuration, a storage pool can be made up of 2 performance tiers (types of disks) with different RAID types.

The Unity array is able to provide both block level and file level storage. For block level resources click Block and iSCSI Interfaces. Use the add button to add iSCSI interfaces for use with block level storage, chose the interface(s), storage pool, and configure the networking settings. LUNs can be created and mapped to a host, subnet, or netgroup using the LUNs tab.

For file level resources click File and NAS Servers, click the add symbol to create a NAS server, chose the interface(s), storage pool, configure the networking settings, and select the sharing protocols to use. It is good practise to create at least one NAS server each on SPA and SPB, and distribute resources evenly. Once your NAS servers are ready you can create File Systems, and then SMB shares or NFS Shares using the appropriate tabs.

During the creating of storage objects such as LUNs or file systems, you have the option to configure snapshots and replication. These features can also be configured at a later date by selecting the storage object and clicking the edit icon. Snapshots can be configured using one of the built in policies or creating your own under the Data Protection section above. When creating replication sessions you need to specify a replication schedule and target.

The VMware page can be used to configure VVOLs, read more about this at Configuring VVOLs with EMC Unity.


Events and Support

The Events page lists all alerts from information to critical, as well as a record of all jobs that have been initiated on the device. The Support page provides links to documentation, training, and support.