Dell VMware User Manual
H18633
Best Practices
Dell EMC Unity: VMware Site Recovery
Manager Best Practices
Abstract
This document offers best practices for automated disaster recovery of
virtualized workloads using Dell EMC™ Unity™ arrays, replication, and
VMware® Site Recovery Manager™.
January 2021
Revisions
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Revisions
Date
Description
January 2021
Initial release
Acknowledgments
Author: Jason Boche
The information in this publication is provided “as is.” Dell Inc. makes no representations or warranties of any kind with respect to the information in this
publication, and specifically disclaims implied warranties of merchantability or fitness for a particular purpose.
Use, copying, and distribution of any software described in this publication requires an applicable software license.
Copyright © 2021 Dell Inc. or its subsidiaries. All Rights Reserved. Dell Technologies, Dell, EMC, Dell EMC and other trademarks are trademarks of Dell
Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners. [1/19/2021] [Best Practices] [H18633]
Table of contents
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Table of contents
Revisions............................................................................................................................................................................. 2
Acknowledgments ............................................................................................................................................................... 2
Table of contents ................................................................................................................................................................ 3
Executive summary ............................................................................................................................................................. 5
Audience ............................................................................................................................................................................. 5
1 Introduction ................................................................................................................................................................... 6
1.1 Dell EMC Unity overview .................................................................................................................................... 6
1.2 Terminology ........................................................................................................................................................ 6
2 Setup prerequisites ...................................................................................................................................................... 9
2.1 Storage Replication Adapter ............................................................................................................................... 9
2.2 Dell EMC Unity and Unity XT ............................................................................................................................. 9
2.3 VMware vSphere and SRM ................................................................................................................................ 9
3 Site Recovery Manager architecture .......................................................................................................................... 10
3.1 Array-based replication: single protected site .................................................................................................. 10
3.2 Array-based replication: dual protected site ..................................................................................................... 11
3.3 vSphere replication: single protected site ......................................................................................................... 12
3.4 vSphere replication: dual protected site ........................................................................................................... 13
4 Unisphere configuration ............................................................................................................................................. 14
4.1 Unisphere availability ........................................................................................................................................ 14
4.2 Unisphere logins ............................................................................................................................................... 14
4.3 Creating dedicated SRA access accounts ....................................................................................................... 15
4.4 Modifying SRM settings for larger environments .............................................................................................. 16
5 Replication configuration ............................................................................................................................................ 18
5.1 Synchronous replication ................................................................................................................................... 19
5.2 Asynchronous replication and snapshots ......................................................................................................... 21
5.3 VMware NFS datastore replication ................................................................................................................... 25
5.4 Snapshots and application consistency ........................................................................................................... 27
5.5 Custom recovery tasks ..................................................................................................................................... 28
6 Site Recovery Manager configuration ........................................................................................................................ 29
6.1 SRA installation ................................................................................................................................................ 29
6.2 Configuring the array managers ....................................................................................................................... 29
6.3 Creating array pairs .......................................................................................................................................... 32
6.4 Array manager device discovery ...................................................................................................................... 32
6.5 Creating placeholder datastores ....................................................................................................................... 33
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6.6 Protection group considerations ....................................................................................................................... 33
6.7 Recovery plan considerations .......................................................................................................................... 34
7 Recovery plan testing and running ............................................................................................................................. 35
8 Reprotect and failback ................................................................................................................................................ 38
8.1 Reprotection ..................................................................................................................................................... 38
8.2 Failback ............................................................................................................................................................ 39
9 Conclusion .................................................................................................................................................................. 40
A Additional resources ................................................................................................................................................... 41
A.1 Technical support and resources ..................................................................................................................... 41
A.2 VMware support ................................................................................................................................................ 41
Executive summary
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Executive summary
Data-center consolidation by way of x86 virtualization is a trend that has gained tremendous momentum and
offers many benefits. Although the physical nature of a server is transformed once it is virtualized, the
necessity for data protection remains. Virtualization opens the door to new and flexible opportunities in data
protection, data recovery, replication, and business continuity. This document offers best practices for
automated disaster recovery of virtualized workloads using Dell EMC™ Unity™, replication, and VMware®
Site Recovery Manager™ (SRM).
Audience
This document is intended for IT administrators, storage architects, partners, and Dell Technologies™
employees. This audience also includes individuals who may evaluate, acquire, manage, operate, or design a
Dell EMC networked storage environment using Dell EMC Unity systems.
Introduction
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1 Introduction
This paper provides configuration examples, tips, recommended settings, and other storage guidelines to
follow while integrating VMware Site Recovery Manager (SRM) with Dell EMC Unity. Besides basic
configuration, this document also answers frequently asked questions about VMware interactions with Site
Recovery Manager.
We recommend reading the Site Recovery Manager documentation provided on vmware.com before
beginning an SRM implementation.
1.1 Dell EMC Unity overview
In this constantly changing world of increasing complexity and scale, the need for an easy-to-use, intelligent
storage system has only grown greater. Customers using new applications and solutions require dependable
storage and are often tasked with the challenge of doing more with less. The Dell EMC Unity and Unity XT
family addresses this challenge by packaging a powerful storage system into a cost and space-efficient
profile.
Dell EMC Unity storage sets new standards for midrange storage. It offers a powerful combination of
simplicity, modern design, affordable price point, and deployment flexibility—perfect for resource-constrained
IT professionals in large or small companies. Dell EMC Unity systems are perfect for midsized deployments,
remote office/branch office locations, and cost-sensitive mixed-workload environments. They are designed for
all-flash, deliver the best value, and are available in several configurations. These configurations include
purpose-built (all-flash or hybrid), converged deployment (through the Converged Infrastructure Portfolio), and
software-defined virtual edition. With all-inclusive software, new differentiated features, internet-enabled
management, and a modern design, Dell EMC Unity storage is where powerful meets simplicity.
1.2 Terminology
The following terms are used with Dell EMC Unity.
Asynchronous replication: Replication method which allows replicating data over long distances and
maintaining a replica at a destination site. Updates to the destination image can be issued manually, or
automatically based on a customizable recovery point objective (RPO).
Bandwidth: Amount of data, represented in MB/s, which can be transferred in a given period.
Common base: Pair of snapshots that are taken on a replication source and destination storage resource
which have the same point-in-time image.
Destination storage resource: Storage resource that is used for disaster recovery in a replication session.
This term is also known as a target image.
Fibre Channel (FC) protocol: Protocol used to perform IP and SCSI commands over a Fibre Channel
network.
File system: Storage resource that can be accessed through file-sharing protocols such as SMB or NFS.
Fracture Log: A bitmap held in persistent memory on each storage processor. The fracture log indicates
which physical areas of a source resource participating in a synchronous replication session have been
updated since communication was interrupted (fracture).
Introduction
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Internal snapshot (replication snapshot): Unified snapshots created by the system that are part of an
asynchronous replication session. These snapshots can be viewed in Dell EMC Unisphere™, but user
operations are not permitted. Each asynchronous replication session uses two internal snapshots taken on
the source and destination storage resources.
iSCSI: Provides a mechanism for accessing block-level data storage over network connections.
LUN: A block-based storage resource which a user provisions. It represents a SCSI logical unit.
Network-attached storage (NAS) server: File-level storage server used to host file systems. A NAS server
is required to create file systems that use SMB or NFS shares.
Network File System (NFS): An access protocol that allows data access from Linux® or UNIX® hosts on a
network.
RecoverPoint for Virtual Machines: Protects virtual machines (VMs) in a VMware environment with VM-
level granularity and provides local or remote replication for any point-in-time recovery. This feature is
integrated with VMware vCenter® and has integrated orchestration and automation capabilities.
Recovery point objective (RPO): Acceptable amount of data, which is measured in units of time, that may
be lost due to a failure. For example, if a storage resource has a one-hour RPO, data that is written to the
storage resource within the last hour may be lost when the replication session is failed over to the destination
storage resource.
Recovery time objective (RTO): Duration of time in which a business process must be restored after a
disaster recovery plan is run. For example, an RTO of one hour requires restoring data access within one
hour after a disaster is declared and the disaster recovery plan performed.
Remote systems: Relationship that is configured between two Unity systems.
Replication session: Relationship that is configured between two storage resources of the same type on
different systems, and automatically synchronizes data from one resource to another.
Server Message Block (SMB): Network file-sharing protocol, also known as CIFS, that is used by Microsoft
®
Windows
®
environments. SMB is used to provide access to files and folders to Windows hosts on a network.
Snapshot: Also called a unified snapshot, a snapshot is a point-in-time view of a storage resource or data
stored on a storage resource. A user can recover files from a snapshot, restore a storage resource from a
snapshot, or provide snapshot data access to a host. When a snapshot is taken, it creates an exact copy of
the source storage resource and shares all blocks of data with it. As data changes on the source, new blocks
are allocated and written to. Unified snapshot technology can be used to take a snapshot of a block or file
storage resource.
Storage resource: Top-level object that a user can provision which is associated with a specific quantity of
storage. All host access and data-protection activities are performed at this level. In this document, storage
resources refer to resources that support replication such as volumes, volume groups, and thin clones.
Synchronous replication: Replication method in which the host initiates a write to the system at a local site,
and the data must be successfully stored in both local and remote sites before an acknowledgment is sent
back to the host.
Thin clone: Read/write copy of a thin block storage resource (volume, volume group, or VMware vSphere
VMFS datastore) that shares blocks with the parent resource.
Introduction
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Unisphere: A web-based Dell EMC management interface for creating storage resources and configuring
and scheduling protection of stored data on a Dell EMC Unity system. Unisphere can be used for all
management of Dell EMC Unity native replication.
Unisphere Manager for RecoverPoint: Web-based interface for managing RecoverPoint replication. It
serves as a single pane of glass for replicating storage resources of multiple storage systems that are
configured to use RecoverPoint. Consistency groups are created, replicated, and recovered through this
interface.
User snapshot: Snapshot that is created manually by the user or by a schedule. This snapshot type is
different than an internal snapshot, which the system takes automatically using asynchronous replication.
Virtual Volumes (vVols): VMware storage framework which allows VM data to be stored on individual
VMware vSphere Virtual Volumes™. This ability allows data services to be applied at a VM-granularity level
while using Storage Policy Based Management (SPBM).
Volume: A block-level storage device that can be shared out using a protocol such as iSCSI or Fibre
Channel. It represents a SCSI logical unit.
Volume group: Storage instance which contains one or more volumes within a storage system. Volume
groups can be configured with write-order consistency and help organize the storage that is allocated for
particular hosts.
vStorage API for Array Integration (VAAI): VMware API that allows storage-related tasks to be offloaded to
the storage system.
vSphere API for Storage Awareness (VASA): VMware API that provides additional insight about the
storage capabilities in vSphere.
Write Intent Log: A record stored in persistent memory on the Dell EMC Unity storage system which tracks
in-flight writes between systems participating in synchronous replication.
Setup prerequisites
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2 Setup prerequisites
Verify the solution requirements listed in this section before deploying or upgrading your environment.
2.1 Storage Replication Adapter
You must install the Dell EMC Unity Storage Replication Adapter (SRA) on each SRM server. Dell EMC Unity
offers SRAs for both the Photon operating-system-based SRM appliance and the Windows-based SRM
installation. Also, Dell EMC Unity offers an SRA for block storage and an SRA for file storage. You can
download the SRAs from the VMware website. Dell Technologies recommends using the most current version
of the SRA to ensure optimal compatibility and available features. See the SRA release notes and product
documentation to determine SRA compatibility with SRM versions.
Note: See the SRA release notes for specific requirements or features for the SRA.
2.2 Dell EMC Unity and Unity XT
SRM- and array-based replication of block or file datastores requires two Dell EMC Unity or Unity XT systems
replicating between each other in one or both directions. Asynchronous and Synchronous replication is
supported for both bock and file datastores. This support includes MetroSync (synchronous replication of NAS
servers and associated storage resources such as NFS datastores and snapshots). You can use SRM with
vSphere replication to protect virtual machines that are backed by vVols.
2.3 VMware vSphere and SRM
Compatible versions of VMware SRM, VMware vCenter™ Server, and vSphere hosts are required. To see a
list of software versions required for SRM, check the VMware Product Interoperability Matrix. SRM is
supported with vCenter Server for Essentials, vCenter Server Foundation, and vCenter Server Standard.
Site Recovery Manager architecture
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3 Site Recovery Manager architecture
This section describes array-based replication architecture for single- and dual-protected sites.
3.1 Array-based replication: single protected site
This configuration (shown in Figure 1) is generally used when the secondary site does not have any virtual
machines that SRM must protect. The secondary site exists solely for disaster-recovery purposes. The
infrastructure at the recovery site must be available and online to run the SRM recovery plan.
Architecture for a single protected site with array-based replication
Site Recovery Manager architecture
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3.2 Array-based replication: dual protected site
This configuration (shown in Figure 2) is generally used when both sites have virtual machines that need to
be protected by SRM. Each site replicates its virtual machines to the opposing site where they can be
recovered.
Architecture for a dual protected site with array-based replication
Site Recovery Manager architecture
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3.3 vSphere replication: single protected site
vSphere replication can be used in addition to or in place of array-based replication (see Figure 3). Here are
two of the main advantages of vSphere replication over array-based replication:
• It enables a granular selection of individual powered-on VMs to be replicated instead of entire
datastores of VMs.
• vSphere datastore objects abstract the underlying storage vendor, model, protocol, and type. This
behavior means that replication can be carried out between different array models and protocols,
including local storage.
vSphere replication, along with other feature support for vSphere replication added in SRM 5.1, makes SRM
appealing and adaptable as a DR solution for organizations with storage or budget constraints.
Configuration for a single protected site with vSphere replication
Site Recovery Manager architecture
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3.4 vSphere replication: dual protected site
vSphere replication also supports the active/active site model (see Figure 4). In each vSphere replication
architecture diagram, replication is handled by the vSphere hosts that use the vSphere network stack. An
array-based SRA is not present in vSphere replication architecture. These figures do not represent all the
components of vSphere replication. A deployment of vSphere replication consists of multiple virtual
appliances at each site and on each vSphere host that handles the movement of data between sites. Go to
VMware Documentation for a detailed look at vSphere replication.
Configuration for a dual-protected site with vSphere replication
Note: You can use vSphere replication to replicate virtual machines that are backed by vVols.
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