White Paper Business Continuity and Disaster Recovery Requirements for a Virtualized World By Mark Bowker and David A. Chapa June, 2011 This ESG White Paper was commissioned by Zerto and is distributed under license from ESG. 2011, Enterprise Strategy Group, Inc. All Rights Reserved
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 2 Contents Virtualization and Mission-critical Applications... 3 Replication Roadblock... 4 Challenges of Traditional BC/DR in Virtual Environments... 4 Enterprise Tier-1 Application Data Protection Needs... 4 New Replication Possibilities Enabled By Virtualization... 6 Hypervisor-based Replication?... 6 Virtual Replication to the Cloud... 6 DR as a Service Could Lead Enterprise Data into the Cloud... 7 BC/DR Needs for Virtualized Mission-critical Applications... 7 The Bigger Truth... 9 All trademark names are property of their respective companies. Information contained in this publication has been obtained by sources The Enterprise Strategy Group (ESG) considers to be reliable but is not warranted by ESG. This publication may contain opinions of ESG, which are subject to change from time to time. This publication is copyrighted by The Enterprise Strategy Group, Inc. Any reproduction or redistribution of this publication, in whole or in part, whether in hard-copy format, electronically, or otherwise to persons not authorized to receive it, without the express consent of the Enterprise Strategy Group, Inc., is in violation of U.S. copyright law and will be subject to an action for civil damages and, if applicable, criminal prosecution. Should you have any questions, please contact ESG Client Relations at (508) 482-0188.
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 3 Virtualization and Mission-critical Applications In an ESG survey conducted in the fall of 2010, 74% of respondents from large midmarket and enterprise-class organizations said their organizations were currently using server virtualization. They also expected massive expansion in their use of server virtualization over the next two years. While organizations continue to reap consolidation benefits such as reduced costs and greater efficiency, most implementations are focused on lower priority Web applications and file and print services. These consolidation benefits, while exciting, are only the tip of the iceberg. ESG research also noted that as virtual implementations expand and mature, organizations start to gain benefits that infiltrate the organization in particular, streamlined application provisioning, maintenance, availability, and data protection processes. 1 It s a different story for mission-critical, tier-1 applications such as performance-oriented database and transactional applications. Despite its growth and obvious benefits, virtualization of mission-critical applications continues to lag; the significant majority of those surveyed (59%) are not yet virtualizing tier-1 applications. In addition, while 57% have virtualized Web-based applications and 53% have virtualized file and print services, only 35% have virtualized tier-1 databases, 28% ERP, and 27% CRM (see Figure 1). Figure 1. Extent of Application/IT Service Deployment on Production Virtual Machines To what extent has your organization deployed the following applications and/or IT services on virtual machines (VMs) running in a production environment? (Percent of respondents, N=457) Web-based applications 57% 26% 9% 5% 3% File and print services 53% 25% 12% 5% 4% E-mail 46% 25% 17% 9% 4% Corporate portal/collaboration solution (e.g., Microsoft SharePoint) 44% 30% 6% 5% Industry-specific packaged application(s) 44% 29% 6% 6% Tier-2 database (i.e., Oracle Standard, Microsoft SQL, MySQL, etc.) 43% 27% 17% 9% 4% Other basic IT services (e.g., Active Directory, DNS, DHCP) 39% 31% 18% 6% 6% Desktop virtualization 35% 32% 19% 9% 5% Tier-1 database (i.e., Oracle Enterprise, IBM DB2, Sybase, etc.) 35% 28% 17% 14% 6% ERP (Enterprise Resource Planning includes financials, human resources, manufacturing, inventory, etc.) 28% 31% 21% 14% 7% CRM (Customer Relationship Management) 27% 31% 20% 10% 11% 0% 20% 40% 60% 80% 100% Already deployed on production VMs Plan to deploy on production VMs No immediate plans to deploy on production VMs, but we would like to do so No plans to deploy on production VMs Don t know / not applicable Source: Enterprise Strategy Group, 2011. 1 Source: ESG Research Report, The Evolution of Server Virtualization, November 2010.
Replication Roadblock White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 4 One barrier to virtualizing mission-critical applications is the state of virtual machine replication. Organizations cannot afford to play fast and loose with these workloads and therefore require bulletproof data protection. A byproduct of consolidating virtual machines (VMs) is that it introduces additional risk: the failure of any individual server will impact all VMs and application interdependencies on that piece of hardware, and downtime tolerance for tier-1 applications is extremely low. Unfortunately, traditional replication and business continuity/disaster recovery (BC/DR) solutions were built for the physical world, not virtualized environments. Virtualized environments place different demands on the infrastructure and, as a result, existing BC/DR solutions have a hard time delivering the scalability, mobility, and flexibility that enterprise-class applications require. Challenges of Traditional BC/DR in Virtual Environments Storage vendors have spent years perfecting replication solutions to enable business continuity and disaster recovery for physical environments. The rapid ascent of server virtualization has somewhat outpaced their ability to keep up, leaving a gap between traditional replication functions and the needs of the virtual world. Resource contention. The higher server utilization rates achieved by workload consolidation ensure more efficient use of resources. However, simultaneous resource-intensive processes (such as file- or application-level BC/DR) can cause resource contention, creating performance problems across the pool of application workloads sharing these resources. The rate at which many virtual environments scale only exacerbates this problem. Snapshots are only crash consistent. Using snapshots can relieve some resource contention, but are not a good option for tier-1 applications as some only capture crash-consistent images. Mission critical databases need transaction consistent replicas for fast recovery, which snapshots alone cannot efficiently supply. Complexity. Array-based replication for virtual environments is a complex, multi-step process involving multiple infrastructure teams. Virtualization teams have to do a lot of upfront work to identify and map the appropriate storage LUNs; the storage team must move data sets around and reconfigure arrays to create space for the replicas. The process is manual and inflexible and requires ongoing monitoring to ensure completion. It is generally managed at the LUN level, so if an application is running on multiple VMs and multiple hosts, IT must first track down and consolidate storage locations and then define replication policies, all using different tools and applications. The management effort is extreme and its cost may actually negate virtualization s savings. Add to that the mobility of workloads in a virtual server environment such as with VMware s vmotion and Distributed Resource Scheduling (DRS) and virtualization wreaks havoc on traditional replication. Cost. Array-based replication solutions require a remote data center and, while the virtual server paradigm can operate there as well, standard replication requires an identical storage configuration. If the production site uses EMC Symmetrix storage, the remote site must as well. The scale of most virtual server environments makes this an expensive proposition even for large companies and precludes the cloud as a replication option. Delivering an identical storage environment for each customer would be cost prohibitive. Enterprise Tier-1 Application Data Protection Needs Mission-critical applications are typically active 7x24x365, serving clients and end-users; as a result, these enterprise applications demand much higher levels of availability, performance, and protection than their tier-2 and tier-3 brethren. IT administrators are used to this and often provision and configure storage and replication processes to specifically accommodate tier-1 applications. High availability. For many organizations, tier-1 data being unavailable can have significant business consequences not just reduced productivity, but lost revenue, missed market opportunities, dissatisfied customers, reputation damage, and even legal liability. As a result, these applications usually have low recovery time objectives (RTOs) and recovery point objectives (RPOs). Recent ESG research on data protection reveals the importance of tier-1 application data: as Figure 2 shows, more than half (53%) of respondents cannot tolerate even
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 5 one hour of downtime without adverse business impact and nearly one-fifth (18%) cannot tolerate any downtime at all for tier-1 applications. 2 Figure 2. Downtime Tolerance According to Business Value of Data 40% 35% For each of the following tiers of data, please indicate the amount of downtime your organization can tolerate before you experience significant revenue loss or other adverse business impact. (Percent of respondents, N=510) 35% Tier-1 data Tier-2 data Tier-3 data 30% 25% 20% 18% 21% 27% 13% 24% 22% 20% 17% 12% 10% 5% 5% 5% 8% 4% 4% 3% 3% 0% None Less than 1 hour 1 hour to 3 hours 3 hours to 10 hours 10 hours to 24 1 day to 3 days More than 3 hours days Source: Enterprise Strategy Group, 2011. As a result, the replication and disaster recovery processes must not impact the availability of this data, a feat not easily achieved in a virtual server environment. No performance impact. The data protection process also must not slow the performance of mission-critical applications. Replication and disaster recovery processes take CPU overhead, slowing down production applications; a very important factor that is oftentimes overlooked is the performance impact to the application brought on by the very solutions meant to protect its data. For example, the amount of time it takes to quiesce an application or the throttling of writes to complete replication should be weighed when evaluating the overall performance impact. At the enterprise tier-1 level, this is unacceptable. Network safety net. High availability requirements require a fallback mechanism so that replication is not interrupted in the case of network disconnects or degradation. Otherwise, data could be lost and unrecoverable. Many high-end solutions track changes during a network interruption, enabling them to be completed once the connection is reestablished, but again the question is about impact and in this case the impact to recovery in the event a major outage is suffered. How resilient the solution is may be measured by how rapidly data and applications are available after the outage; traditionally, this may require a re-sync of data, which could impact the recovery time objective stated in an SLA. Consistency group support. Enterprise-class replication should support consistency groups to enable rapid application recovery instead of only data recovery. Today s federated applications are usually spread across multiple servers and storage arrays; for virtual applications, this means multiple virtual machines, physical hosts, and storage devices. However, for protection and replication, they require application-level consistency to speed return to full operations the time-consuming alternative involves various storage restores that must be manually re-grouped. In a virtual environment, this requires VM level consistency and cross-vm and cross-storage 2 Source: ESG research Report, 2010 Data Protection Trends, April 2010.
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 6 consistency, such as write order fidelity which is a huge challenge for most replication solutions. This is a must to recover the application and, depending on the IT organization s specific objectives, will dictate its replication needs. ESG believes that this may be one of the top reasons enterprises continue to use storage-based protection with its limited flexibility and mobility. The challenge is exacerbated by the migration of live virtual machines between hosts. Scalability. In virtual environments, tier-1 protection solutions must be able to handle tremendous scaling without jamming the network or becoming a management nightmare. It s not uncommon to scale from five VMs to 500 in a short period of time; traditional replication solutions cannot handle this level of activity. Management. Managing the protected site and the remote site should be simple and efficient. Whether an organization replicates locally, remotely, or to the cloud, management should be simple and integrated and should not require multiple management tools to get the job done. Too much replication management diminishes virtualization s benefits. Application recovery. Today, traditional data protection solutions do a very good job of recovering the data, creating protection policies, and reporting, but recovering an application at a remote site presents new challenges, especially in a virtualized environment. More and more IT organizations are tasked with solution designs to meet SLAs either with the internal customers or external customers of its organization. In some cases, it is becoming more like the early days of backup when all servers and data were grouped in a single backup policy to be protected. While this may have been a reasonable approach with smaller data sets, it caused problems as environments grew and data sets needed to be treated with different retention policies. The same can be true for virtualized environments; for example, a tier-1 application carries different recovery time requirements than a tier- 3 application, so having the ability to configure SLAs on a per virtual machine basis helps improve SLA management. Recovering an application and a virtual machine requires the right configuration, licensing, properties, network, etc. and time to recover is largely determined by those variables. A solution that can replicate and manage the intricacies of the relationships between virtual machines and applications will provide a higher degree of recovery automation in the event of a crisis. New Replication Possibilities Enabled By Virtualization When virtualization first became a viable technology, replication and virtualization were almost mutually exclusive workloads important enough to need replication were not considered virtualization targets. Today, mission-critical applications are being virtualized and must also be replicated. Hypervisor-based Replication? As virtualization matured, more functionality moved from devices into the hypervisor. Many infrastructure functions that require application visibility can now be managed at the hypervisor level tasks such as resource allocation, load balancing, and even analytics and network security. Could replication move to the hypervisor as well? It has been mentioned on some product roadmaps, but is not yet a reality. SAN-based replication works well for the physical environment, but hypervisor-based replication could solve some challenges for enterprise applications, particularly performance and availability. Virtualization and server administrators are reaching into the storage domain and managing processes there as products like VMware vcenter take on more and more of the infrastructure, operations, and application management tasks. Virtual Replication to the Cloud Virtualization may enable replication to the cloud, reducing costs associated with maintaining an identical remote site. Replication occurring in the hypervisor instead of the storage array can eliminate the need for identical storage at the replication site. What if cloud providers could provide vendor- and protocol-agnostic replication, offering replication from any storage type to any other storage type? This would be quite a feat. Each side would benefit: the enterprise could select the storage that s right for its primary environment and the cloud provider could select the appropriate storage for theirs.
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 7 Cloud providers would also need to deliver secure and reliable multi-tenancy in order to replicate data from different customers with full assurance of protection and privacy. Other key attributes would include simple, fast, flexible implementation; easy integration with cloud management systems and Web services APIs; and subscription-based pricing. DR as a Service Could Lead Enterprise Data into the Cloud Enterprises are hesitating to put production data in the cloud. They see the value of it, but being responsible for data for a billion-dollar organization makes one tread carefully into new technologies. Many CIOs are at a crossroad, recognizing the financial benefits of the cloud, but concerned about security, access, and control of their data resources. This tier-1 application data is the lifeblood of the organization, driving revenue and productivity. The cloud offers a tempting opportunity to save both capital and operational expenses as long as mission-critical availability, performance, and protection requirements can be fully met. By removing interoperability issues and enabling any-to-any storage replication options, virtualization can more easily enable DR as a service, simplifying recovery procedures for the enterprise in the event of disaster while reducing costs. Without virtualization, it s expensive even to test recovery, much less actually reserve recovery space. But in a virtual environment, testing is fast and simple, requires fewer resources, and improves reliability by eliminating the risk associated with shipping tapes off site. DR as a service could be the stepping stone enterprises need on their paths to the cloud. Live production data would remain on site, but IT managers would have the opportunity to use the cloud and become more comfortable with the concept. If you implement disaster recovery in the cloud and perform a test failover to the cloud, you have essentially turned on your application in the cloud without moving it. This could be a good way to get a sense of what production data looks like in the cloud and identify any challenges to address. BC/DR Needs for Virtualized Mission-critical Applications Replication may be a roadblock for virtualizing mission-critical applications, but the ongoing maturity of hypervisors brings new possibilities. So what do virtualized, mission-critical applications need for business continuity and disaster recovery? What would a solution need to provide in order to be effective and support the high-level requirements of enterprise-class data? Software only. Appliances and dedicated hardware are expensive to purchase and manage, and don t scale easily. Virtual ready. Managing replication at the LUN level is complicated in a virtual environment; enterpriseclass data needs to be managed at the VM and VMDK levels to minimize management overhead. In a virtual environment, tracking down and consolidating storage locations for applications, as well as identifying the hosts and virtual machines upon which the application is dependent, is too costly. Support for mission-critical application needs. Mission-critical applications require a higher level of functionality than lower tier and IT-focused applications. Any replication solution must ensure write order fidelity for the application and support consistency grouping of virtual machines across hosts and storage. It must also support requirements such as short RTOs and RPOs, near-synchronous replication, continuous data protection, and many-to-one and bidirectional replication. Virtual-aware. Virtual machines can be moved among physical servers; replication should not interfere with that. Replication policies should accompany data sets as they move among hosts and storage arrays. Full application recovery management, including creating and turning on new virtual machines, will speed recovery. Application-aware. The replication solution must be application-aware, replicating and recovering complete applications spread across multiple virtual machines, hosts, and storage locations. Easy management. While business continuity and disaster recovery are critical, their benefits are diminished if they add management complexity and new points of control. A replication solution for
White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 8 virtualized mission-critical applications should be easily integrated with existing management tools. Fast integration and ease of use will also help to ensure rapid and successful adoption of the replication solution. Seamless scalability. It is not unusual for an organization to face a sudden exponential increase in the number of virtual machines deployed. A disaster recovery solution should not hinder that, but should instead grow easily along with the virtualized infrastructure. It should be able to operate and configure policies at the application level without having to purchase, install, and configure additional proprietary hardware. No performance impact. Service interruption and slowing application performance are unacceptable for virtualized mission-critical applications. Reliability. Bandwidth optimization and the ability to immediately and automatically recover from WAN interruptions are crucial. Support for heterogeneous storage in the cloud. This is essential for ensuring flexibility and costeffectiveness. To fully support this, replication solutions should support replication and mobility across not only storage vendors, but storage technologies. Organizations should be able to replicate to a different tier in the primary site and should be able to take advantage of cloud-based replication without changing the production environment.
The Bigger Truth White Paper: Business Continuity and Disaster Recovery: Requirements for a Virtualized World 9 Most large enterprises have mature business continuity and disaster recovery strategies in place. They fully appreciate the importance of high-quality data protection for the applications that run their businesses and they have invested in the appropriate replication solutions, tools, and bandwidth for their physical environments. However, as they move toward greater virtualization, they encounter difficulty with replication built for the physical world. Some are hanging back from further virtualization of these mission-critical applications until they find the type of replication solution that will serve the needs of these applications in the virtual environment. The key questions for these enterprises are: How can I protect mission-critical applications in a virtualized environment in an enterprise-class manner? How can I leverage virtualization and still have RPOs and RTOs of seconds; consistency across multi-tiered, federated applications; no performance impact; and extreme scalability without huge equipment costs and complex operations? A BC/DR solution would need to provide these features and be fully virtual-ready and application-aware, easy to deploy and manage, and able to support on-site, remote site, or cloud-based replication. The virtualization paradigm offers greater flexibility by removing the need for identical storage between the production and protection sites. The cloud could become a replication site as well, and using cloud for DR would enable organizations to test the waters before placing production data in the cloud. These features, enabled by enterprise-class, hypervisor-based replication, could deliver a BC/DR scenario fit for mission-critical data. These solutions will be purpose-built for the virtual environment it is unlikely that any physical solution could be retrofitted adequately to meet the heightening demands of tier-1 application uptime and availability. Solutions with these features could help to break the logjam and enable more virtualization of missioncritical applications; this, in turn, would not only extend virtualization s benefits to more of the enterprise, but also expand the type of benefits, from simple consolidation to more utility-like provisioning.
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