Optimizing NetApp SnapMirror

Technical White Paper Optimizing NetApp SnapMirror WAN Optimization using Riverbed Steelhead appliances Technical White Paper Version 0.1 December 2013

2014 Riverbed Technology. All rights reserved. Riverbed, Cloud Steelhead, Granite, Interceptor, RiOS, Steelhead, Think Fast, Virtual Steelhead, Whitewater, Mazu, Cascade, Shark, AirPcap, BlockStream, SkipWare, TurboCap, WinPcap, Wireshark, TrafficScript, FlyScript, WWOS, and Stingray are trademarks or registered trademarks of Riverbed Technology, Inc. in the United States and other countries. Riverbed and any Riverbed product or service name or logo used herein are trademarks of Riverbed Technology. All other trademarks used herein belong to their respective owners. The trademarks and logos displayed herein cannot be used without the prior written consent of Riverbed Technology or their respective owners. Akamai and the Akamai wave logo are registered trademarks of Akamai Technologies, Inc. SureRoute is a service mark of Akamai. Apple and Mac are registered trademarks of Apple, Incorporated in the United States and in other countries. Cisco is a registered trademark of Cisco Systems, Inc. and its affiliates in the United States and in other countries. EMC, Symmetrix, and SRDF are registered trademarks of EMC Corporation and its affiliates in the United States and in other countries. IBM, iseries, and AS/400 are registered trademarks of IBM Corporation and its affiliates in the United States and in other countries. Linux is a trademark of Linus Torvalds in the United States and in other countries. Microsoft, Windows, Vista, Outlook, and Internet Explorer are trademarks or registered trademarks of Microsoft Corporation in the United States and in other countries. Oracle and JInitiator are trademarks or registered trademarks of Oracle Corporation in the United States and in other countries. UNIX is a registered trademark in the United States and in other countries, exclusively licensed through X/Open Company, Ltd. VMware, ESX, ESXi are trademarks or registered trademarks of VMware, Incorporated in the United States and in other countries. This product includes software developed by the University of California, Berkeley (and its contributors), EMC, and Comtech AHA Corporation. This product is derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm. NetApp Manageability Software Development Kit (NM SDK), including any third-party software available for review with such SDK which can be found at http://communities.netapp.com/docs/doc-1152, and are included in a NOTICES file included within the downloaded files. For a list of open source software (including libraries) used in the development of this software along with associated copyright and license agreements, see the Riverbed Support site at https//support.riverbed.com. This documentation is furnished AS IS and is subject to change without notice and should not be construed as a commitment by Riverbed Technology. This documentation may not be copied, modified or distributed without the express authorization of Riverbed Technology and may be used only in connection with Riverbed products and services. Use, duplication, reproduction, release, modification, disclosure or transfer of this documentation is restricted in accordance with the Federal Acquisition Regulations as applied to civilian agencies and the Defense Federal Acquisition Regulation Supplement as applied to military agencies. This documentation qualifies as commercial computer software documentation and any use by the government shall be governed solely by these terms. All other use is prohibited. Riverbed Technology assumes no responsibility or liability for any errors or inaccuracies that may appear in this documentation. 2014 Riverbed Technology. All rights reserved. 1

Contents PREFACE... 3 About This Guide... 3 Audience... 3 Contacting Riverbed... 4 Internet... 4 Technical Support... 4 Professional Services... 4 Chapter 1 Solution Overview... 5 Benefits of NetApp SnapMirror... 5 Benefits of Riverbed Steelhead WAN optimization... 5 Solution Architecture... 6 Requirements... 6 Chapter 2 Performance Results... 7 Performance in a Typical Scenario... 7 Performance with High-latency and Packet-loss... 8 Performance with Limited Bandwidth... 9 NetApp SnapMirror Visibility and Control... 10 Summary of Best Practices... 11 Conclusion... 11 2014 Riverbed Technology. All rights reserved. 2

PREFACE Welcome to the Optimizing NetApp Replication Solution Guide. Read this preface for an overview of the information provided in this guide and contact information. This preface includes the following sections: About This Guide Contacting Riverbed About This Guide The Optimizing NetApp Replication Solution Guide describes the performance benefits and best-practices associated with the combined solution of NetApp SnapMirror and Riverbed Steelhead WAN optimization appliances. Audience This guide is written for network and storage administrators familiar with administering and managing WANs using NetApp SnapMirror replication protocol. You must also be familiar with: The Management Console. For details, see the Steelhead Management Console User s Guide. Connecting to the RiOS CLI. For details, see the Riverbed Command-Line Interface Reference Manual. The installation and configuration process for the Steelhead appliance. For details, see the Steelhead Appliance Installation and Configuration Guide and the Virtual Steelhead Installation Guide. This guide includes information relevant to the following products: Riverbed Steelhead CX appliance (Steelhead CX) Network Appliance Data Storage Systems For more details on the Steelhead appliance family, see http://www.riverbed.com/products-solutions/products/wan-optimization-steelhead 2014 Riverbed Technology. All rights reserved. 3

Contacting Riverbed This section describes how to contact departments within Riverbed. Internet You can learn about Riverbed products through the company Web site: http://www.riverbed.com. Technical Support If you have problems installing, using, or replacing Riverbed products, contact Riverbed Support or your channel partner who provides support. To contact Riverbed Support, open a trouble ticket by calling 1-888-RVBD-TAC (1-888-782-3822) in the United States and Canada or +1 415 247 7381 outside the United States. You can also go to https://support.riverbed.com. Professional Services Riverbed has a staff of professionals who can help you with installation, provisioning, network redesign, project management, custom designs, consolidation project design, and custom coded solutions. To contact Riverbed Professional Services, email proserve@riverbed.com or go to http://www.riverbed.com/us/products/professional_services. 2014 Riverbed Technology. All rights reserved. 4

Chapter 1 Solution Overview This chapter describes benefits of the combined solution and how NetApp SnapMirror with Riverbed Steelhead WAN optimization can overcome impairments commonly found in wide-area networks, including high latency, packet-loss, and limited bandwidth. This chapter includes the following sections: Benefits of NetApp SnapMirror Benefits of Riverbed Steelhead WAN optimization Solution Architecture Requirements Benefits of NetApp SnapMirror NetApp SnapMirror has been used by thousands of customers worldwide to protect and accelerate their business by replicating their critical data across global networks at high speeds. SnapMirror efficient thin replication is used primarily for disaster recovery, providing the ability to quickly recover from adverse natural or human-made events. As economic pressures increase, IT organizations are becoming more creative with the powerful capabilities of SnapMirror and realizing the benefits of NetApp efficiency technologies to take advantage of the ability to non-disruptively create replicas of live data, improving utilization from the equipment at disaster recovery sites and achieving better efficiencies overall. So whether it is disaster recovery, business intelligence, data distribution, or development and test, SnapMirror provides return on investment with up to 60% lower total cost of ownership (TCO). Benefits of Riverbed Steelhead WAN optimization Riverbed Steelhead WAN optimization solutions improve the performance of business applications and data transfers across the WAN by overcoming the negative effects of high latency, packet loss, and limited bandwidth. Powered by the Riverbed Optimization System (RiOS), Steelhead WAN optimization solutions are capable of improving the performance of business applications by 5 to 50 times and, in some cases, by up to 100 times, while also reducing WAN bandwidth requirements by up-to 95%. Transport Streamlining improves the performance of TCP-based applications by improving the way transport protocols behave on WANs, reducing the number of TCP packets required to transfer data by 65-98 percent. Transport Streamlining overcomes the limitations of TCP by adapting transmission characteristics such as window scale, packetloss handling, congestion notification, and more. Data Streamlining performs real-time byte-level data reduction and compression to dramatically expand the capacity of WAN links. Data streamlining is not limited to a silo of a particular application, but is applied across all application traffic. In this way, unique bytes are sent across the network once even if, for example, they are sent several times by multiple applications such as file, email, web, and/or data replication. RiOS Data Streamlining commonly delivers bandwidth optimization by up-to 5-10x or more. Network QoS and Max-Speed TCP (MX-TCP) overcome the negative effects of packet loss, and give you the ability to easily manage shared WAN infrastructure across applications. Riverbed Network QoS ensures sufficient bandwidth for key applications like VoIP, live video, and thin clients. And by using an advanced Hierarchical Fair Service Curve (HFSC) method for scheduling, real-time applications requiring minimal latency can be provided the service they need without having to overcompensate by statically reserving more bandwidth for such applications. Application Streamlining addresses application-specific bottlenecks in addition to the underlying data streamlining and transport streamlining optimizations. This includes the elimination of costly round-trips over the WAN for chatty file, email, and web applications whose performance degrades dramatically in the presence of increased network latency. 2014 Riverbed Technology. All rights reserved. 5

Solution Architecture Steelhead appliances sit between the NetApp Filers as depicted in the diagram below. The replication traffic is transparently intercepted by the Steelhead appliances and optimized, greatly reducing the time required to synchronize volumes and qtrees across the wide area network. Figure 1-1 Steelhead optimized NetApp replication data topology As a result, organizations can achieve LAN-like performance for NetApp SnapMirror, leading to improved recovery point objectives (RPO). Requirements The following table describes the hardware and software requirements for deploying Steelhead appliances with NetApp SnapMirror. Requirement Riverbed Steelhead CX appliances with RiOS 8.5 or later Network Appliance Storage System Notes A Riverbed Steelhead appliance is required at each site as depicted in Figure 1-1 Valid NetApp SnapMirror license required 2014 Riverbed Technology. All rights reserved. 6

Chapter 2 Performance Results This chapter describes the relative performance gains when using Steelhead WAN optimization. It includes the following sections: Performance in a Typical Scenario Performance with High-latency and Packet-loss Performance with Limited Bandwidth NetApp SnapMirror Visibility and Control Summary of Best Practices Conclusion Performance in a Typical Scenario This section describes the relative performance gains when using Steelhead WAN optimization for a typical remote replication scenario using a common data set. Table 1-1: SnapMirror performance: 80ms, 0.1% packet-loss, 155 Mbps WAN) SnapMirror SnapMirror + Steelhead Data Set Total Bytes Written Time to Complete Replication Time to Complete Replication Performance Increase Corporate Email 6.7 GB 24.0 Minutes 1.9 Minutes 13x Virtual Machines 6.3 GB 25.8 Minutes 1.6 Minutes 16x Financial Database 33.4 GB 4.4 Hours 9.8 Minutes 27x For this scenario, replication performance was evaluated using typical levels of WAN latency, packet-loss and capacity: Latency 80 ms RTT (North America coast-to-coast) Packet Loss 0.1% (MPLS network) Capacity 155 Mbps (OC-3) In the cases without Steelhead WAN Optimization, SnapMirror network compression was enabled. In the cases with Steelhead WAN Optimization, SnapMirror network compression was disabled. (See section, Summary of Best Practices, for additional configuration guidelines.) Performance was evaluated separately for three application data sets, which were written to storage and replicated by SnapMirror across the WAN. A single volume was used for each data set. For each test, the time delta between the first and last byte replicated across the WAN was measured. Performance gains with Riverbed WAN optimization seen in this test can be attributed to three key aspects of the combined solution: 1. Riverbed MX-TCP provides consistent throughput (Mbps) across WANs with latency and packet loss. 2. Riverbed Data Streamlining provides increased WAN bandwidth optimization (x-factor). 3. Maximum SnapMirror throughput (MB/s) is increased when SnapMirror network compression is offloaded to Riverbed Steelhead appliances. In the sections that follow, each of these aspects is investigated in further detail. 2014 Riverbed Technology. All rights reserved. 7

Performance with High-latency and Packet-loss This section describes the results of a test scenario designed to measure the effects of using Steelhead WAN optimization to overcome the negative effects of packet-loss and high latencies. Table 1-2: SnapMirror performance: 155 Mbps WAN, variable latency and packet-loss Unoptimized WAN Steelhead-optimized WAN Latency Packet Loss Throughput Throughput Performance Increase 20-80 ms 0.0% 139 Mbps 141 Mbps 1x 20 ms 0.1% 23 Mbps 141 Mbps 6x 20 ms 1.0% 8 Mbps 139 Mbps 17x 80 ms 0.1% 7.5 Mbps 140 Mbps 19x 80 ms 1.0% 1.9 Mbps 132 Mbps 69x 100 ms 0.1% 3.3 Mbps 140 Mbps 42x 100 ms 1.0% 1.4 Mbps 134 Mbps 96x These results show that when packet-loss is present in a WAN, end-to-end throughput for SnapMirror replication can decrease dramatically. This decrease is a natural by-product of how TCP (the underlying network transport protocol) reacts when packetloss is present in a network. In such environments, end-to-end throughput is significantly lower than what the WAN could otherwise support based on its available capacity. With Steelhead WAN Optimization, as exhibited in this test scenario, maximum throughput can be maintained even in the presence of high levels of both latency and packet-loss. This increase in performance is a result of leveraging RiOS MX-TCP for optimized transport between Steelhead appliances. With no packet loss, SnapMirror was able to deliver throughput close to the theoretical maximum for the 155 Mbps WAN, even for latencies up-to 100 ms RTT. However, when even small amounts of packet-loss (0.1%) are present in the network, end-to-end throughput degrades dramatically. The values for latency and packet loss used in this test scenario are representative of real-world WAN characteristics: Table 1-3: Latency and Loss characteristics Latency Packet Loss 20 ms - Regional / Interstate 0.0% - Dedicated point-to-point WAN 80 ms - North America (Coast-to-Coast) 0.1% - MPLS network 100ms - Cross-continent (e.g., NY-to-London) 1.0% - VPN over Internet For this test scenario, WAN capacity was set to 155 Gbps (OC-3). WAN data reduction techniques were disabled to isolate core network protocol performance (TCP) in each scenario. 2014 Riverbed Technology. All rights reserved. 8

Performance with Limited Bandwidth As illustrated in the previous section, the first step in delivering optimized performance across a WAN involves making full use of WAN resources, even when faced with high levels of latency and packet-loss. The next step involves expanding the capacity of the WAN through the use of network compression and/or data de-duplication techniques. Such techniques transform a sequence of packets to be transmitted across the WAN into a smaller sequence of packets. In this way, the amount of data logically transmitted across the WAN can exceed the raw capacity of the WAN itself. This result is often referred to a bandwidth optimization or network data reduction, and it is defined in terms of the ratio between total bytes and actual bytes sent across the WAN. For example, with a Bandwidth Optimization of 2x achieved through compression and/or de-duplication, a WAN link of 100 Mbps would be capable of transmitting 200 Mbps of end-to-end throughput. The level of bandwidth optimization delivered depends on the nature of the data being sent and the data reduction algorithms being applied. Table 1-4 shows the level of data reduction delivered by NetApp SnapMirror network compression and Riverbed Steelhead WAN Optimization appliances for three different data sets. Each data set was replicated twice, recording the data reduction delivered in each case. The CPU utilization on the NetApp storage system was recorded for each SnapMirror transfer. Table 1-4: SnapMirror Performance: Bandwidth Reduction table SnapMirror-native SnapMirror-native Network Network Compression (1st Compression (2nd Pass) Pass) Data Set Corporate Email Virtual Machines Financial Database WAN Bandwidth Optimization Storage System CPU Utilization WAN Bandwidth Optimization Storage System CPU Utilization Riverbed Steelhead Data Streamlining (1st Pass) WAN Bandwidth Optimization Storage System CPU Utilization Riverbed Steelhead Data Streamlining (2nd Pass) WAN Bandwidth Optimization Storage System CPU Utilization 5.7x 99% 5.7 x 99% 9x 16% 54x 16% 2.8x 99% 2.8 x 99% 11x 5% 51x 5% 2.9x 99% 2.9 x 99% 4.3x 11% 26x 11% In all cases, the level of bandwidth optimization was increased by Steelhead WAN optimization. The increase in bandwidth optimization can be attributed to a few key factors: RiOS Data Streamlining uses a de-duplication scheme which is both (i) fine-grain in its ability to detect repetitive bytelevel sequences and (ii) scalable in its ability to refer to large sequences of information with small 16-byte references. Steelhead appliances are built with high-capacity datastores, which provide the ability to recall more byte patterns sent further back in time. RiOS Data Streamlining is applied at the network transport level, across all applications traversing the WAN. This allows, for example, three types of transport: 1. data saved in an office document over the WAN, 2. then sent as an email attachment across the WAN, and 3. then sent as replication traffic to traverse the WAN only once. There is another positive side-effect that results from offloading WAN compression from the NetApp storage system to the Steelhead WAN optimization appliances. Namely, the amount of storage system CPU required to transfer the data is dramatically reduced. When NetApp native compression is used, storage system CPUs were fully utilized (99%). When data reduction processing is offloaded to the Steelhead WAN optimization appliances, the NetApp storage system CPU resources were dramatically reduced, which would allow the storage system to apply more processing power to its core I/O operations. 2014 Riverbed Technology. All rights reserved. 9

NetApp SnapMirror Visibility and Control Today, when NetApp SnapMirror sends data to a network, the network sees and treats all packets as essentially the same. Yet, in reality, different packets originate from different storage volumes, which manage data for different applications (for example, databases, email, virtual servers, etc.) that may have different SLAs defined by the business, such as Recovery Point and Recovery Time Objectives (RPO/RTO). RiOS provides users with complete visibility and total control over the performance of SnapMirror across the WAN and allows you to: Tune optimization settings for any volume to yield maximum performance. Control WAN bandwidth allocation and network Quality of Service (QoS) for individual volumes to reflect business priority. Track throughput and data reduction for individual filers and volumes, as well as for SnapMirror as a whole. In this example, NetApp SnapMirror is replicating an email qtree, a database volume, and a virtual machine volume from the source filer to the destination filer. The optimization policy for each volume/qtree is defined in the table below: Table 1-5: RiOS SnapMirror Optimization Page The SnapMirror report displays how much benefit SnapMirror optimization is providing for a given filer (or all filers) and traffic type in the time period specified. You can use this report to view optimization outcomes for a filer, all volumes and qtrees for a single filer, or a single filer for a volume or qtree. You can also drill down to specific optimization statistics for a volume or a qtree. Table 1-6: RiOS SnapMirror Optimization Report Table 1-6 clearly shows that the SnapMirror policy defined in Table 1-5 is being enforced. The email qtree replication set has the highest priority followed up by the database volume and the virtual machine volume. 2014 Riverbed Technology. All rights reserved. 10

Summary of Best Practices The following list describes key best practices when using Steelhead WAN Optimization with NetApp SnapMirror replication. For more information, consult vendor product documentation and technical support representatives. To overcome the negative effects of WAN packet-loss (e.g., MPLS or VPN over Internet infrastructure), utilize Riverbed MX-TCP. To maximize WAN bandwidth optimization and NetApp storage system performance, disable SnapMirror network compression and utilize Riverbed Data Streamlining. When SnapMirror shares the same WAN resource with other business applications, use Riverbed Steelhead network QoS to enforce minimum bandwidth guarantees for SnapMirror traffic. To fine-tune optimization and prioritize NetApp SnapMirror replication traffic on a per-volume or per-qtree level, utilize Riverbed RiOS SnapMirror optimization. Conclusion The performance of NetApp SnapMirror can be negatively impacted by characteristics common to widearea networks, including packet loss, latency, and limited bandwidth. Steelhead WAN optimization appliances can be leveraged to overcome the negative effects of these impairments, delivering LAN-like performance for NetApp SnapMirror and all other business applications traversing the WAN. The result of testing identified the following conditions where NetApp SnapMirror combined with Steelhead WAN Optimization is particularly beneficial: WAN links with latency of 20 ms RTT or higher (e.g., interstate, cross-country, international) and with packet-loss rates of 0.1% or higher (e.g., MPLS or VPN over Internet). The performance of data replication decreases exponentially as latency and packet loss increase. Riverbed Steelhead WAN optimization ensures that WAN capacity is fully utilized, even when faced with high levels of both packet-loss and/or latency. Limited WAN capacity impairs the ability to meet Recovery Point and/or Time Objectives (RPO/RTO). Riverbed Steelhead WAN optimization dramatically reduces WAN capacity requirements, allowing RPO/RTO objectives to be met or exceeded while reducing the TCO of WAN infrastructure. WAN links are shared by NetApp SnapMirror and other business applications or data transfers. Riverbed WAN optimization provides more WAN capacity for SnapMirror by minimizing the WAN footprint of other applications. In addition, Riverbed s advanced Network QoS capabilities ensure proper allocation of shared WAN resources to SnapMirror so that RPO/RTO objectives can be met, even in the presence of WAN traffic from competing sources. Riverbed Technology, Inc. 199 Fremont Street San Francisco, CA 94105 Tel: (415) 247-8800 www.riverbed.com Riverbed Technology Ltd. One Thames Valley Wokingham Road, Level 2 Bracknell. RG42 1NG United Kingdom Tel: +44 1344 31 7100 Riverbed Technology Pte. Ltd. 391A Orchard Road #22-06/10 Ngee Ann City Tower A Singapore 238873 Tel: +65 6508-7400 Riverbed Technology K.K. Shiba-Koen Plaza Building 9F 3-6-9, Shiba, Minato-ku Tokyo, Japan 105-0014 Tel: +81 3 5419 1990 2014 Riverbed Technology. All rights reserved. 11