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SAP Disaster Recovery Solution with VMware Site Recovery Manager and EMC CLARiiON

Applied Technology

Abstract

This white paper demonstrates how VMware’s Site Recovery Manager enables the design of a powerful yet simple disaster recovery solution. Built on the solid foundation of VMware virtualization and leveraging EMC® MirrorView™/Synchronous storage replication technology, Site Recovery Manager easily resolves typical disaster recovery challenges in an extremely cost-effective manner while providing complete flexibility.

January 2009

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Part Number h6047.1

SAP Disaster Recovery Solution with VMware SRM and EMC CLARiiON Applied Technology 2

Table of Contents Executive summary ............................................................................................4 Introduction.........................................................................................................4

Audience ...................................................................................................................................... 4 Solution components .........................................................................................4

EMC CLARiiON CX4 series storage............................................................................................ 4 EMC MirrorView........................................................................................................................... 5 EMC SnapView............................................................................................................................ 6 VMware Site Recovery Manager ................................................................................................. 6 SAP.............................................................................................................................................. 7 Microsoft Active Directory ............................................................................................................ 8

Solution design and setup .................................................................................8 Architecture diagrams .................................................................................................................. 8 Hardware and software.............................................................................................................. 10

Hardware and software configuration .................................................................................... 13 Site Recovery Manager installation and configuration .............................................................. 13

Primary site and secondary site ............................................................................................. 13 Disaster recovery testing .................................................................................14

Recovery plan test using Site Recovery Manager..................................................................... 15 Conclusion ........................................................................................................20 References ........................................................................................................21


Executive summary More and more mission-critical business applications are now logically combined into distributed, multi-tier (also called n-tier) client/server platforms. The SAP business suite of applications is an example of an n-tier application. Companies that have deployed the SAP product suite depend heavily on the information, processes, and availability of the environment, even in the case of a disaster. However, the complexity and distributed nature of these applications make implementation and maintenance of traditional disaster recovery solutions expensive and complicated. The costs, stringent requirements, and complexities of such solutions often deter smaller businesses, given their limited budgets and staff. As a result, they are left with few options for protecting their applications and their businesses.

VMware virtualization technology helps overcome the challenge of achieving high availability. This white paper introduces an approach to disaster recovery that uses VMware Site Recovery Manager and EMC® CLARiiON® storage technology to provide an effective availability solution for mission-critical SAP deployments running in a Microsoft Windows environment.

Introduction This white paper outlines how, in a multi-tier SAP environment that resides on EMC CLARiiON storage, VMware® Site Recovery Manager can help you:

• Accelerate recovery for the virtual environment through automation • Ensure reliable recovery by enabling non-disruptive testing • Simplify recovery by eliminating complex manual recovery steps and centralizing management of

recovery plans The scope of the architecture documented here includes:

• Fresh installation of SAP ECC 6.0 on MSSQL Server 2005, Windows Server 2003, Microsoft Active Directory, and EMC CLARiiON CX4 storage

• Storage array technology used to replicate LUNs (via EMC MirrorView™/Synchronous) between two separate CLARiiON storage systems to provide data consistency across the primary and secondary site

• Setup of a Protection group and recovery plan consisting of a three-tier SAP environment using VMware Site Recovery Manager

• Execution of a non-disruptive test of the recovery plan. This test included recovering the SAP solutions at a secondary site while the primary site was subjected to a load created by SGEN transactions

Audience This white paper is intended for EMC employees, partners, IT managers, storage architects, database administrators, and consultants who are involved in planning for disaster recovery options for their SAP on Windows application deployments.

Solution components

EMC CLARiiON CX4 series storage Enterprises use EMC CLARiiON systems as their midrange storage for its price-performance benefits while maintaining enterprise-class scalability, reliability, and availability for mission-critical applications. The CLARiiON CX4 series storage platform, launched in the third quarter of 2008, is EMC’s state-of-the-art midrange family of storage systems. The CX4 features a 64-bit enhanced FLARE® driver for increased scaling and operational capability and a new UltraFlex™ I/O module design. UltraFlex technology allows


additional front-end connection ports to be added to increase connection paths from servers to the CLARiiON or additional back-end connections to the spindles depending on specific requirements that can vary for different deployments. The flexible design of the CX4 incorporates the ability to upgrade to new higher-bandwidth connection technologies, such as 10 Gigabit Ethernet or 8 Gigabit Fibre Channel, as they become available. As shown in Figure 1, the CLARiiON CX4 offers combined iSCSI and Fibre Channel connectivity (available in all storage models within the CX4 family). This feature empowers storage administrators to optimize predictable performance based on application service levels.

Figure 1. EMC CLARiiON CX4 storage and VMware

This platform delivers unmatched scalability – up to 960 drives and 4,096 LUNs with the CX4-960 model – for accommodating a multitude of drive types ranging from extremely high performance drives to extremely dense drives. The result is not only good scaling in total capacity but also storage tiering to allow for the most cost-effective manner of storing and managing SAP solutions. For additional information on the CLARiiON CX4 UltraScale series, refer to the EMC website.

Two CX4-480 storage arrays with MirrorView/Synchronous (MirrorView/S) were used in the VMware Site Recovery Manager and SAP application use case discussed in this paper. The methodologies discussed here are valid for all models in the CLARiiON family that support MirrorView/S, including the CX, CX3, and the latest CLARiiON storage model, the CX4 series.

EMC MirrorView EMC MirrorView is storage system-based disaster recovery software that provides end-to-end data protection by replicating the contents of a primary volume to a secondary volume residing on a different CLARiiON storage system. It provides end-to-end protection because, in addition to performing replication, it protects the secondary volume from tampering or corruption by making the volume only available for server access when initiated through MirrorView. MirrorView offers a feature called consistency groups, a unique consistency technology that replicates a set of write-order dependent volumes. Using this technology, MirrorView maintains write ordering across the secondary volumes in the event of an interruption to one, some, or all of the write-dependent secondary volumes. For this solution we used MirrorView/S mode to ensure an RPO of zero.


http://www.emc.com/products/series/cx4-series.htm

Figure 2. EMC MirrorView/S software

As shown in Figure 2, all I/O from the local host is first written to the local storage processor memory and is then sent over the mirroring links to the remote CLARiiON unit. Once the remote CLARiiON unit reports that the data has reached its storage processor memory successfully, the I/O is acknowledged to the local host. Synchronous mode guarantees that the remote image is a complete duplication of the source image

EMC SnapView EMC SnapView™ enables the creation of local point-in-time snapshots and complete data clones for testing, backup, and recovery operations. With SnapView, multiple copies of production data can be created within EMC CLARiiON storage systems quickly and easily. SnapView snapshot technology is used by Site Recovery Manager to validate recovery plans quickly without interruption to the production environment at the primary site.

VMware Site Recovery Manager VMware Site Recovery Manager is a disaster recovery management and automation solution for VMware Infrastructure. Site Recovery Manager accelerates recovery by automating the recovery process and simplifying the management of disaster recovery plans. It makes disaster recovery an integrated element of managing your VMware virtual infrastructure. The solution ensures reliable recovery by eliminating complex manual recovery steps and enabling non-disruptive testing of recovery plans. Site Recovery Manager integrates tightly with VMware Infrastructure, VMware vCenter, and EMC’s MirrorView software to make failover and recovery rapid, reliable, affordable, and manageable. It enables organizations to take the risk and worry out of disaster recovery, as well as expand protection to all of their important systems and applications.

Figure 3 depicts the technical architecture of Site Recovery Manager with storage array replication across two sites.


Figure 3. Site Recovery Manager with MirrorView/S Site Recovery Manager is a plug-in to vCenter, so disaster recovery tasks can be executed from the same centralized interface that is used to manage other virtual machine administrative tasks such as creation, migration, deletion, and so forth. However, Site Recovery Manager is not a built-in component of vCenter; it is a separate server process with its own separate database. The server processes for Site Recovery Manager and vCenter can co-exist on the same server or reside on different servers. Similarly, both Site Recovery Manager and vCenter data repositories can be created in a single database or in separate databases.

Site Recovery Manager does not actually perform the replication for disaster recovery but facilitates the setup, test, and recovery workflows. Site Recovery Manager relies on block-based replication (fiber or iSCSI) from VMware storage partners for replication. In this case, EMC CLARiiON MirrorView/S was used. Storage replication adapters that are developed, qualified, and supported by the storage vendor manage the communication between Site Recovery Manager and the storage replication. These adapters exist on the Site Recovery Manager server and once installed are invisible for the duration of their use.

SAP SAP provides a range of enterprise software applications and business solutions to manage and run the complete business of a company. In addition to ERP software, other key SAP products and solutions include business intelligence, customer relationship management, supply chain management, supplier relationship management, human resource management, product life cycle management, enterprise portal software, and knowledge warehouse software.

SAP applications are based on the SAP NetWeaver application and integration platform. SAP enterprise applications can be deployed in a two- or three-tiered architecture. The three-tiered client/server architecture generally consists of a presentation layer, an application layer, and a database layer. These three layers can run separately on different computers or together on the same computer, depending on the requirements and size of the SAP solution being deployed. In three-tiered configurations, the database and application services reside on separate operating system images, whereas in two-tiered configurations, they co-exist on the same OS image. The three-tiered architecture scales to support a large numbers of users.

Site 1

CLARiiON CX4-480 1

MirrorView SW

VCMS 1 DB

SRM 1 DB

VC Server 1

SRM Server 1

Storage Replication

Adapter

Site 2

CLARiiON CX4-480 2

MirrorView SW

VC Server 2

SRM 2 DB SRM Server 2

Storage Replication

Adapter

VCMS 2 DB


The two-tiered architecture is usually sufficient for many smaller and midsize companies, as well as for sandbox, development, training, and test systems.

Microsoft Active Directory Active Directory (AD) provides a variety of network services, including LDAP-like directory services, Kerberos-based authentication, DNS-based naming, and other network information. AD stores information and settings in a central database, for use primarily in Windows environments.

AD is a framework that consists of logical objects like forests, trees, and domains. SAP recommends the installation of SAP software on Windows be performed in a Windows domain.

The simple AD architecture documented here consists of a primary domain controller on the primary site and a secondary domain controller on the secondary site. Customer deployments that involve more complex setups and the topologies of such configurations are available in the Microsoft documentation (see the “References” section on page 21 for more information).

Solution design and setup

Architecture diagrams Figure 4 highlights the logical architecture for this solution. Disaster recovery testing with Site Recovery Manager requires that the virtual machines in the secondary site start from storage that is copied from the target LUNs (on secondary site). This practice ensures the test is run against a storage infrastructure that is isolated from the production environment - as shown in Figure 4 and covered in more detail later.


Figure 4. Logical architecture: Site Recovery Manager setup with CLARiiON CX4 storage


Figure 5. Physical architecture: Site Recovery Manager setup with CLARiiON CX4 storage

Hardware and software The following table lists the software and hardware used in the architecture.

Table 1. Hardware and software components

VMware

VMware Infrastructure 3 vCenter Server 2.5 VMware ESX 3.5 U 2

Site Recovery Manager Site Recovery Manager 1.0

EMC

Storage system CLARiiON CX4-480

Features and software MirrorView/Synchronous Storage configuration 7 LUNs:

LUN 1: 100 GB OS LUN LUN 2: 100 GB, database data LUN 3: 50 GB, database log LUN 4: 50 GB, database tempdb LUN 5: 100 GB, SAP application server LUN 6 on primary (not replicated): 50 GB, Active Directory main domain controller LUN 7 on secondary: 50 GB, secondary domain controller


SAP

SAP ECC 6.0 Virtual Machine "sapdb" Database virtual machine (VM) Also runs the SAP Central Instance 2 x vCPU 8 GB RAM Windows Server 2003 SP1 64-bit MSSQL 2005 Database SID = "PRD" Storage - 4 x volume (4 x LUNs): OS on 1 x VMFS LUN data on 1 x VMFS LUN log on 1 x VMFS LUN temp on 1 x VMFS LUN Virtual Machine "dialog" Application Tier virtual machine (VM) 2 x vCPU 8 GB RAM Windows Server 2003 SP1 64-bit Storage - 1 x volume (1 x LUNs)

Dell

Blade servers running ESX Dell PowerEdge 2950 4 core (2.8 GHz) 16 GB RAM 4 Gb QLogic HBA card

Microsoft

Active Directory Virtual Machine "ACTIVEDIR" Primary domain controller + DNS on primary site domain = "enterprise.sap.com� " Virtual Machine "DC 2" Secondary domain controller + DNS on secondary site

The screenshots that follow show the configuration of the database and application server virtual machines.


Figure 6. Configuration of the SAP database and the Central Instance virtual machine

Figure 7. Configuration of the SAP application server virtual machine

Key points about this setup:

• The ESX host server at the primary site has two SAP virtual machines. A database virtual machine hosts MSSQL 2005 and the SAP Central Instance. The second virtual machine hosts an SAP dialog instance.

• Active Directory and DNS are installed in a virtual machine (running Windows Server 2003) on a non-replicated LUN on the primary site. A secondary domain controller and DNS are installed in a virtual


machine (running Windows Server 2003) on a LUN on the secondary site. This domain controller is part of the same forest and domain, "enterprise.sap.com."

• Site Recovery Manager requires two vCenter servers - one each at the primary and secondary sites. For this solution (built in a lab), we used one ESX host machine to run the primary and secondary site vCenter servers configured in virtual machines. However, it is a best practice to separate primary and secondary site vCenter host servers for disaster recovery practices.

• Primary and secondary site storage consists of EMC CLARiiON CX4 Fibre Channel storage arrays. For data replication, EMC MirrorView/S is configured to replicate all the SAP-related LUNs from primary to secondary storage.

• The EMC Storage Replication Adapter (SRA) is installed on the primary and secondary vCenter servers. The EMC SRA: • Automatically discovers the replicated LUNs on the primary site • Facilitates a Site Recovery Manager test recovery workflow on the secondary site during failover

by creating a clone of replicated LUNs (based on SnapView). • The primary site containing all the SAP virtual machines is logically combined into one Site Recovery

Manager protection group called “SAP”. This protection group is created on the primary vCenter server.

• At the recovery site a recovery plan called “SAP” is created on VCenter.

Hardware and software configuration The hardware and software were installed and configured in the following order:

• Configure EMC storage arrays at the primary and secondary sites (each array per each site). • Create LUNs as described on the primary site storage and expose to the primary site ESX host server. • After creating and configuring the virtual machines with operating systems and patches, install Active

Directory on the primary site and the second domain controller on the secondary site, then install SAP. • Install vCenter Server 2.5 on two Windows virtual machines. These virtual machines will serve as

primary and secondary site vCenter Server instances. • Configure storage replication between primary and secondary site storage arrays:

• Configure MirrorView/S to replicate five LUNs (database and application server). • Create a Consistency Group containing these five LUNs. This unique feature ensures appropriate

I/O ordering at the remote site in case of failover. • Install and configure Site Recovery Manager on the primary and secondary vCenter Server instances

(see the next section).

Site Recovery Manager installation and configuration A high-level overview of Site Recovery Manager installation and configuration is discussed next. For detailed configuration steps please consult the appropriate VMware product manuals and guides.

Primary site and secondary site • Install the Site Recovery Manager server into a separate database instance on the same guest OS

running vCenter Server • Install the Site Recovery Manager plug-in into vCenter • Install EMC Storage Replication Adapter (SRA) on the guest OS of the vCenter virtual machines After installation, the Site Recovery Manager plug-in is available and can be accessed via the VMware Infrastructure (VI) Client. Figure 8 shows a screenshot of the primary vCenter Server defining the configuration steps required after the initial installation.


Figure 8. Primary site Site Recovery Manager server immediately after installation As shown in Figure 8, execute the configuration steps to configure Site Recovery Manager.

At the primary site:

• Configure the connection between primary and secondary Site Recovery Manager servers • Configure the array manager • Configure inventory preferences • Create a protection group “SAP” for the virtual machines at the primary site

At the secondary site:

• Create a recovery plan “SAP” consisting of group “SAP” • Prioritize the virtual machine start order to start the database and SAP Central Instance virtual machine

first followed by the SAP dialog instance virtual machine • Create a customization specification for the database and dialog virtual machines. The virtual

machines are started up on the secondary site on a different subnet from the primary site. • Configure the virtual machines in the “SAP” recovery plan to use the customization specifications

created in the previous step

Disaster recovery testing Disaster recovery testing comprises a logistical plan for how an organization will recover and restore partially or completely interrupted critical function(s) within a predetermined time after a disaster or extended disruption. This logistical plan is commonly referred to as the Business Continuity Plan. The old


saying goes that any disaster recovery plan is only as good as your last (successful) test. Indeed, most disaster recovery efforts fail as a result of one of two factors: the team either spends an inordinate amount of effort conducting continuous tests or — worse —neglects to test often, the result being an insurance policy that doesn't pay off when you really need it.

Disaster recovery testing is often difficult because it is usually very disruptive, expensive in terms of resources, and extremely complex. By leveraging virtualization, VMware Site Recovery Manager addresses this problem while making planning and testing simpler to execute. Site Recovery Manager has the ability to create a “virtual remote recovery image” — storage, virtual machines, even network connections — and test this image as a walled-off virtual entity, perhaps even co-resident with production apps that might be running at the remote site. This ability to logically encapsulate and test a complete recovery scenario in a set of virtual machines is a huge simplification of the task and saves significant time and resources.

You can run frequent tests that simulate an actual recovery by running a recovery plan test. Site Recovery Manager runs exactly the same plan for both tests and actual recoveries with the following exceptions:

• Recovery tests do not connect to the primary site and shut down virtual machines. • Recovery tests create test networks so that the infrastructure of the primary and secondary site is

protected. The test network is removed after the test is completed, ensuring the protection of the infrastructure of both the protection and recovery site. You can, however, select an actual network to test recovery (as shown in this solution).

The recovery plan test for our solution is described next.

Recovery plan test using Site Recovery Manager The following sequence is executed to validate the recovery plan test during a period when the SAP system is under load:

1. On the primary site, start a batch job in SAP.

2. Start a Site Recovery Manager disaster recovery test on the secondary site for recovery plan “SAP”. Meanwhile the SAP system on the primary site is not impacted and continues processing the batch job until completion.

3. Once the recovery plan test completes, click Continue to ensure proper cleanup.

These steps are covered in detail on the following pages.

On the primary site, execute SGEN in SAP and submit a batch job.


Figure 9. SAP Transaction SM37 showing the SGEN batch job on the primary site

Once the batch job starts executing, initiate a test of the recovery plan on the secondary site. The figures that follow show the recovery plan execution and recovered virtual machines on the secondary site.


Figure 10. Site Recovery Manager recovery plan in test mode

Figure 11. Recovered SAP database and application server virtual machines (secondary site)


During the recovery plan test, the EMC Site Recovery Manager adapter creates snapshots of the replicated SAP LUNs. The SAP virtual machines in these snapshots are recovered and verified on the secondary site. Figure 12 depicts EMC Navisphere

®

Manager showing the snapshots (Navisphere is EMC's GUI-based tool to manage the storage array).

Figure 12. EMC snapshots created during a recovery plan test at the secondary site Once the site recovery is complete, log in to SAP and verify the status of the previously submitted batch job. As expected, it indicates a “cancelled” status.


Figure 13. Status of the batch job failed on the recovered SAP system at the secondary site

Verify the timestamp of the last record processed by the SGEN batch job on the secondary site – this should correspond approximately to the time when the test plan was initiated (this is expected as the storage replication is synchronous).


Figure 14. Timestamp of the last records processed by Batch Job SGEN (Database table REPOLOAD)

Click Continue in the recovery plan, as shown in Figure 10 on page 17, to complete the recovery test and clean up the storage (this removes the snapshots).

Conclusion This paper demonstrates how VMware Site Recovery Manager enables the design of an effective and automated disaster recovery solution. Using a multi-tier SAP environment residing on EMC CLARiiON storage, we highlighted how Site Recovery Manager lets you:

• Accelerate recovery for the virtual environment through automation. The recovery of SAP virtual machines into a different subnet on the secondary site is fully automated.

• Ensure reliable recovery by enabling non-disruptive testing. Recovery plan testing can be conducted as many times as required to satisfy auditing requirements.

• Simplify recovery by eliminating complex manual recovery steps and centralizing management of recovery plans.

The use case shown here is based on Windows and uses Active Directory to provide infrastructure naming services. Domain controllers are not replicated by the storage software and recovered by Site Recovery Manager — separate domain controllers and DNS exist at the primary and secondary sites.

Traditional disaster recovery solutions are slow and prone to failures because they involve many manual and complex steps that are difficult to test, and require expensive duplication of the production data center


infrastructure to ensure reliable recovery. VMware Site Recovery Manager is designed to simplify and automate the disaster recovery process so that you can reliably recover from data center outages in hours rather than days. Working with VMware Infrastructure, VMware Site Recovery Manager can help eliminate the complexity and unreliability of manual recovery and do away with the cost and complexity of maintaining duplicate but idle infrastructure at a recovery site.

References EMC.com • EMC CLARiiON CX4 Series datasheet • EMC CLARiiON Integration with VMware ESX Server white paper • VMware ESX Server Using EMC CLARiiON Storage Systems Solutions Guide • Maintaining End-to-End Service Levels for VMware Virtual Machines Using VMware DRS and EMC

Navisphere QoS white paper Microsoft.com • Microsoft Active Directory overview • Active Directory Forest Topologies • Active Directory Replication VMware.com • VMware and SAP solutions page • VMware virtualization products page • VMware Site Recovery Manager Administration Guide • VMware Site Recovery Manager 1.0 Release Notes • Simplify Database Management with VMware Virtual Infrastructure 3 and CLARiiON Storage


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SAP Disaster Recovery Solution with VMware Site · PDF fileSAP Disaster Recovery Solution with VMware ... disaster recovery challenges in an extremely cost-effective manner while