A COMPREHENSIVE APPROACH TO APPLICATION AVAILABILITY

Transcription

1 NETAPP WHITEPAPER A COMPREHENSIVE APPROACH TO APPLICATION AVAILABILITY Subra Mohan October 2006 WP EXCEPTIONAL DATA AVAILABILITY WITH ARCHITECTURAL SIMPLICITY, FAST DATA RECOVERY, ROBUST STORAGE RESILIENCY, AND AFFORDABLE DISASTER RECOVERY SOLUTIONS Organizations must be able to maintain application availability during planned or unplanned downtime and have the ability to quickly reestablish full functionality in case of a disaster. In this paper, we will explore the different types of failures that can cause applications to be unavailable and discuss how the NetApp storage infrastructure helps you address these failures on the storage side by offering unsurpassed data availability with its architectural simplicity, storage resiliency, fast data recovery, and costeffective replication solutions that enable you to protect more of your applications.

2 TABLE OF CONTENTS 1 INTRODUCTION CAUSES OF APPLICATION DOWNTIME NETAPP OFFERS EXCEPTIONAL DATA AVAILABILITY CONCLUSION

3 1 INTRODUCTION Businesses are under relentless pressure to improve application availability, striving for 100% availability for mission-critical applications. Revenue cannot be generated unless the business is up and running. Due to the increasing dependency of businesses on their IT organization and the increasing cost of downtime, organizations are focusing on the various causes of outages and adopting a systematic approach to reducing the risks of downtime. Not only do IT organizations need to address the typical infrastructure issues, but they also need to address the people and process issues and put in place a plan to quickly recover from unforeseen disasters. Recent disasters such as 9/11, hurricane Katrina, and the tsunami in Indonesia have caused many organizations to reconsider their approach to risk management and disaster planning. Organizations recognize that disasters and disruptions will occur. Their focus has changed from disaster avoidance to disaster recovery. And the definition of disaster has been broadened to include all sorts of disruptions both naturally occurring and manmade. This paper explores the different obstacles to improving application availability and explains how the NetApp storage infrastructure uniquely addresses these challenges to provide superior data availability and speedy recovery from disaster. 2 CAUSES OF APPLICATION DOWNTIME There are two categories of application downtime: planned and unplanned. Failures of one type or another are, for the most part, unavoidable and can lead to unplanned downtime. Improving application availability not only depends on preventing unscheduled downtime and recovering seamlessly from unexpected hardware and software failures, but it also depends on the ability of administrators and operators to perform their daily tasks without reducing the availability of system resources. PLANNED DOWNTIME From a storage perspective, tasks such as increasing storage capacity, adding adapter cards to expand I/O connectivity, updating firmware or the storage operating system, and removing and replacing failed hardware components typically require maintenance downtime. To minimize or eliminate maintenance downtime, organizations need solutions that allow on-the-fly provisioning and enable nondisruptive upgrades. UNPLANNED DOWNTIME There are many potential reasons for unplanned downtime, including operational failures, application failures, component and system failures, site failures, and regional disasters. Common causes of each type of failure are detailed below. 3

4 Figure 1 Potential causes of unplanned downtime. The consequences of unplanned downtime can be disastrous. When data availability or integrity is compromised through failures of any type, businesses risk lost revenue and market share, decreased productivity, reduced competitiveness, damaged brand reputation, eroded customer loyalty, and the consequences of regulatory noncompliance. There are two main planning guidelines for recovering from unplanned downtime: Recovery Time Objective (RTO) and Recovery Point Objective (RPO). RTO is the amount of time you need to recover from lost or damaged data or failover to a disaster recovery site seconds, minutes, hours, days. RPO defines the amount of time for which work may be lost in the event of an unplanned outage at the primary site. It is used to define how frequently backup copies are made or how often data is replicated to the disaster recovery site. This frequency determines how much data loss an organization is willing to tolerate less frequent backups or replications translate into more data loss. It also determines which type of disaster recovery solution is right for you synchronous or asynchronous replication. According to a Gartner Data Center Survey from April 15, 2005, 40% of unplanned downtime is caused by operational failures (operator errors); another 40% is caused by application failures; and the remaining 20% is caused by system and component failures, environmental failures, and disasters. Storage system failures account for a negligible percentage of all system and component failures as a result of the storage resiliency features built into all of the most widely used systems. Operational Failures The proliferation of storage silos, multiple architectures, products, and technologies that are not interoperable are making IT infrastructures increasingly complex. This complexity often results in a rise in operator errors. Companies need to simplify and unify architectures and technologies to prevent such operator errors. When operator errors do occur, companies must be able to quickly recover from recent copies of the data. Application Failures Information fuels business. Mission-critical business applications such as ERP and CRM give employees in offices around the world access to accurate, up-to-date, business-critical information. As new functionality is continually added to applications that need to support multiple underlying architectures, complexity increases and the likelihood of an application failure rises. Keeping these applications up and running is vital to keeping the business alive and generating revenue. Enterprises are continually looking for tightly integrated, cost- 4

5 efficient solutions with fast and flexible recovery processes to minimize their application downtime and increase employee productivity. System and Component Failures Failures in system components often result in long recovery times and data corruption. A high level of storage resiliency is essential to preventing downtime and data loss. Organizations need a comprehensive storage resiliency infrastructure with fully redundant, fault-tolerant hardware to avoid single points of failure (SPOF) without compromising performance or incurring excessive cost. Site and Regional Failures Of the different types of unplanned downtime, site failures and regional disasters are the least likely to occur, but they are responsible for the highest costs when they do happen. Figure 2 Downtime probability. Because of the extreme costs associated with replicating primary storage to a remote site, many companies do not have a valid disaster recovery solution in place. However, after recent disasters, such as the 9/11 event, the hurricanes and floods in New Orleans, the tsunami in Indonesia, and increasing government regulations surrounding data security, companies are compelled to address disaster recovery for a broader set of their business applications. But to justify the investment, they must be able to do this cost-effectively. 3 NETAPP OFFERS EXCEPTIONAL DATA AVAILABILITY Improved application availability and speedy disaster recovery require a storage architecture that protects against all planned and unplanned downtime and allows quick recovery when downtime does occur. The NetApp storage solution is a comprehensive offering that addresses all causes of application downtime preventing operator errors, recovering from operator and application errors, minimizing planned downtime, maximizing system uptime, and recovering from disaster. By following best practice methodologies, users of the extensive NetApp portfolio of storage hardware and software and outstanding service and support have been able to achieve % availability for the most demanding missioncritical enterprise data center environments. 5

6 Figure 3 NetApp data availability and disaster recovery solutions. PREVENTING OPERATOR ERROR Storage vendors have addressed high system uptime requirements with full hardware redundancy and various RAID implementations. However, most have yet to focus on the most frequent cause of application downtime: operator error. The complexity of today s IT infrastructures has created a sharp increase in operator error from pulling wrong cables or power cords to planning inappropriately for memory, disk capacity, or power and cooling to accidentally deleting files. Traditionally, managing this complexity has been the domain of the storage equipment vendor's Professional Services organization. The unique NetApp approach is to focus on preventing operator errors by simplifying and unifying storage and data management software and processes. Unified Architecture The NetApp data availability solution starts with unified storage architecture. Every NetApp storage product offers simultaneous support for Fibre Channel SAN, IP SAN, and network-attached storage (NAS). And while other vendors offer platforms that demand different software and processes for different tiers and types of storage, the NetApp unified storage architecture uses just one set of software and processes across all tiers of storage, greatly simplifying the complexities of enterprise data management. A single process for activities such as installation, provisioning, mirroring, backup, and upgrading is used throughout our entire product line, lowering administrative costs and making it easier to deploy new capabilities across all tiers of storage significantly reducing the opportunities for operator error. The NetApp unified storage architecture and manageability software simplifies the process of deploying and managing the storage infrastructure, reducing the likelihood of operator errors during setup and limiting the use of Professional Services to value-add activities such as assessment and design. 6

7 RECOVERING FROM OPERATOR ERROR When operator errors do happen, recovery of recent data or archived data must happen quickly in minutes, not days. Fast Recovery of Recent Data NetApp Snapshot technology enables nearinstantaneous, space-efficient, online backups of large datasets without impacting system performance. This makes it possible to perform frequent backups at any time throughout the day, ensuring near current copies of data. But, even better, data stored in Snapshot copies can be accessed easily and directly for immediate recovery. SnapRestore works with Snapshot, enabling you to revert an entire file system to an earlier stored Snapshot copy within seconds. Fast Recovery of Archived Data NetApp SnapVault provides fast, centralized, and cost-effective disk-to-disk backup by replicating Snapshot copies to inexpensive secondary storage and eliminating redundant data across each backup. Data stored in these vaulted Snapshot copies can be accessed directly for immediate recovery of data. Disk-to-disk backup offers faster backup and recovery times and has a lower TCO than tape when you take into account the reduced capacity requirements provided through data de-duplication and the simplified backup management. Full copies of data can be stored in a fraction of the space required by tape. Disks also offer higher levels of reliability, availability, and data integrity than tape. Disk-to-disk backup with SnapVault allows data to be replicated efficiently across a WAN for offsite protection, eliminating the risks associated with tapes being lost, stolen, or damaged. MAINTAINING APPLICATION UPTIME Data availability with minimal downtime is a business imperative, especially since database downtime is measured in thousands of dollars per minute. NetApp storage solutions are tightly integrated with key business applications from Oracle, Microsoft, SAP, Symantec, and IBM to help organizations of all sizes optimize their IT and business processes. This tight integration enables application and database administrators to manage their own data and be less reliant on storage administrators for tasks such as backup and recovery or database cloning for testing and development. Application Integration SnapManager provides integrated backup and recovery for Oracle and Microsoft (Exchange and SQL Server) applications. Its wizard-based GUI allows application administrators to perform frequent and efficient backups in seconds, leveraging the speed and efficiency of NetApp Snapshot technology. SnapManager Microsoft and Oracle integration also enables it to complete full data recovery in minutes, rather than hours or days. This application-centric view allows SnapManager to restore with application-level granularity. SnapManager is integrated with SnapMirror to enable disaster recovery from an application-specific viewpoint. And, unlike most other implementations, SnapManager can be deployed without the need for Professional Services. MINIMIZING PLANNED DOWNTIME Organizations need to be able to quickly adapt and react to changing business demands. Expanding I/O capacity, replacing failed disks, and updating firmware are all part of maintaining and upgrading storage systems to keep up with business 7

8 demands. Planned downtime cannot be avoided, but it can be minimized. NetApp storage systems offer built-in technologies that allow maintenance and upgrade tasks to be completed with virtually no interruption to service. On-the-Fly Provisioning FlexVol technology automatically pools storage resources and enables administrators to create multiple flexible volumes on a large pool of disks. With thin provisioning and flexible volumes, storage can quickly be provisioned and reprovisioned by dynamically configuring volumes based on actual usage and reallocating storage between various LUNs, volumes, and aggregates without affecting applications or databases. Additional storage capacity can be added as needed and allocated on the fly to the most appropriate applications or departments. Nondisruptive Scalable Storage Expansion With NetApp storage systems, you have the ability to expand storage capacity nondisruptively for existing loops. Our rack-mountable modular design allows you to simply and quickly add expansion disk shelves without requiring downtime by daisy-chaining new shelves to existing ones (up to a maximum of six shelves per loop). If you want further granularity, NetApp also allows the addition of single disk drives to an existing disk shelf with available drive slots by simply and quickly hot-adding disk drives one at a time as their capacity or spindle performance needs change. Nondisruptive Upgrades Nondisruptive upgrade (NDU) technology provides a simple and reliable method for upgrading software and hardware on a dualcontroller storage cluster. The nondisruptive upgrade is done via a takeover and giveback in each direction in the cluster, always keeping one controller alive. The storage controller that has been taken over can then have hardware components added or replaced and software or firmware updated with minimal disruption. Firmware for Fibre Channel (FC) shelves and disks can be upgraded nondisruptively without cluster failover. Dual ESH2 modules can seamlessly upgrade FC shelf firmware without downtime or clustered failover. In addition, individual FC drives can upgrade firmware using the Momentary Disk Offline feature, which enables nondisruptive updates without requiring clustered failover. MAXIMIZING SYSTEM UPTIME To help maintain application availability and data integrity, storage resiliency the ability to prevent and quickly recover from errors and system failures is built into every aspect of the Network Appliance storage architecture. We offer a comprehensive portfolio of storage resiliency technologies that effectively protect against storage and media failures without compromising performance, costeffectiveness, simplicity, and scalability. For more information on NetApp storage resiliency technologies, please see the NetApp publication Storage Resiliency without Compromise. Data ONTAP Storage Resiliency Software Dual-parity RAID (RAID-DP) is the industry s best implementation of RAID6, protecting against double disk failures with better performance than other implementations of RAID6 and dramatically better cost efficiency than RAID1/10/0+1. SyncMirror combines disk array mirroring with RAID-DP to provide data protection that is superior to conventional mirroring while maintaining the read performance advantages of RAID1. The NetApp Maintenance Center suite of Data ONTAP resiliency software proactively identifies and fixes issues before they can do harm. Our unique Lost Write Signatures technology and our Momentary Disk Offline capability enable unresponsive drive problems to be fixed without affecting system performance. Fully Redundant Hardware Every NetApp storage system provides industrystandard hardware redundancy. All system components are 100% fully redundant and fault tolerant to avoid single points of failure to ensure the highest availability for 8

9 business-critical applications. NetApp is the first to offer quad pathing for active/active systems in a Multipath HA Storage back-end configuration for enhanced availability and performance consistency. SuportEdge Services Outstanding support is essential to the success of enterprise IT operations. Responding to problems after they occur is no longer enough. Potential problems must be anticipated and prevented to ensure the highest possible performance, data availability, and operational efficiency. Storage Availability Audits, a key feature of NetApp support offerings, provides periodic, indepth reviews of the health of the storage systems to identify potential problems before they impact availability. Combined with expert advice on how to maintain the systems in their peak operational state, NetApp support services help reduce the risk of downtime. RECOVERING FROM DISASTER Most organizations implement disaster recovery solutions that focus on protecting only the top 5% 10% of mission-critical applications via synchronous replication, with no cost-effective solution for the rest of the business-critical applications. The NetApp storage infrastructure extends the umbrella of coverage and allows you to cost-effectively implement a disaster recovery solution that protects a broader set of applications against disaster. Our Disaster Recovery (DR) portfolio offers synchronous replication solutions that ensure zero data loss, semi-synchronous replication solutions that support RPOs in seconds with negligible impact on the host application, and asynchronous replication solutions that can meet RPOs ranging from one minute to one day. There are several considerations to be made when deciding which type of disaster recovery solution to implement: Is your goal high availability, ongoing backup and recovery, or remote recovery in the event of a site disaster? Which applications need protection? Not all applications are equal, so you need to tier applications based on how critical they are and have different sets of RPOs for each application tier. What is your RPO in case of a disaster? A zero RPO implies no data loss, which can only be addressed by a synchronous replication solution. This requires a high-bandwidth network and can only mirror sites that are no more than 100 km apart. If you can afford to go with a higher RPO, an asynchronous replication solution with RPO in minutes or hours is much more flexible and cost-effective and has the ability to provide coverage for more of your applications. What is your RTO in case of a disaster? How far away from the primary storage site will the disaster recovery site be located? This will depend on the likely geographic impact of the disaster that you are protecting against. Many large organizations tend to mirror between their existing geographically distributed data centers as it eliminates the cost of setting up a new DR site. Synchronous Replication for Site Failures NetApp MetroCluster software is a zero- RPO solution that helps protect against site disasters and hardware outages within a campus or metro environment. MetroCluster provides the ability to stretch a storage cluster so that the second set of storage controllers and storage arrays is located in a different building or site. This approach is a unique and innovative integration of high-availability clusters and site failover capability. Such an approach 9

10 provides automatic failover for any component failure and a single-click failover for major site failures without incurring any data loss. Not only does this solution reduce the overall cost of deployment, single-click storage failover also reduces downtime and a dual storage plex configuration improves overall read performance from simultaneous read operations occurring on both storage plexes. Except for a few mission-critical applications that demand storage clusters at both the primary and secondary data centers, the cost-effectiveness of this solution makes it ideal for most applications. SnapMirror Sync is a more traditional disaster recovery solution that meets the requirement of zero data loss. SnapMirror Sync is a flexible solution that allows a storage cluster at each site to be mirrored to one another to provide an additional level of availability. SnapMirror Sync is simple to deploy, taking only minutes to set up with minimal training, thus reducing IT costs without requiring expensive Professional Services resources. The SnapMirror Sync simple recovery process also reduces the likelihood of operator errors and ensures quick recovery from disaster. Asynchronous Replication for Regional Failures SnapMirror Async is a flexible, cost-effective DR solution that can be deployed across long distances, providing protection against regional disasters. SnapMirror Async leverages Snapshot technology whereby only block-level incremental changes are transmitted over the wire, ensuring efficient storage and network bandwidth utilization. SnapMirror Async can replicate from Fibre Channel primary storage to cheaper DR storage using ATA disks, lowering the cost of deploying the DR site. SnapMirror also leverages existing IP networks to reduce networking infrastructure costs. Because of the unified NetApp architecture, all NetApp storage systems have both FC and GigE ports, so there is no need for an additional FC-to-IP converter when replicating over IP networks. Expanded DR Site Usability Not only does SnapMirror Async reduce overall TCO, but by enabling you to put the DR site to active business use, it also makes it easier to justify the cost of the DR investment for non-mission-critical applications. By combining SnapMirror Async with FlexClone, space-efficient data copies can be created on the DR storage for other uses, such as application testing, QA, and production staging, without impacting the production system. SnapMirror Async also provides a readable mirror copy, enabling centralized backup of data to tape from multiple data centers thus reducing investment in tape infrastructure as well as offloading the production system from tape backups. This readable access (without breaking mirror copy) also enables you to distribute corporate data to remote sites, optimizing network bandwidth usage and offloading the production system from remote read accesses. Professional Services Planning and design consultation from NetApp Professional Services helps take the complexity out of deploying a high availability and disaster recovery solution. Typically, each engagement starts with an Assessment Service in which we work with you to understand your business objectives regarding high availability and disaster recovery. We then help you choose the right solution based on the uptime requirements of your application environments, which disasters you are protecting against (to determine the location of the DR site), your RPO and RTO requirements, and your budget. We then design a solution that addresses the above requirements and leverages NetApp best practice methodologies. Based on the approved design, we can quickly implement the solution, speeding time to production. Our flexible engagement model enables us to work either as part of your IT team or to drive the entire project ourselves. The ultimate goal of Professional Services is to enable you to get the most out of our solutions. 10

11 4 CONCLUSION All storage vendors deliver availability, but not all focus on delivering solutions for the most frequent causes of downtime: operational and application failure. NetApp delivers a unified storage architecture with solutions that address all causes of downtime, from the most likely type of failure (operator error) to the least likely but most costly type of failure (regional disasters). The simplified, unified storage architecture from NetApp results in reduced operator errors (storage admins, application admins, backup admins) and leads to increased application uptime. Competitive solutions create storage silos for specific applications that lead to increased complexity and more operator errors. Storage uptimes of % can be achieved with NetApp systems by following documented best practices and taking advantage of storage resiliency features such as RAID- DP, redundant connections, and SyncMirror software. NetApp systems can also proactively identify problems in disk drives and correct them before a failure happens. With its superior Snapshot implementation, SnapManager products, and disk-to-disk backup portfolio, NetApp delivers fast recovery of recent data and fast recovery of archived data with minimal data loss. Site and natural disasters are less likely than operator error, but they can have a much greater impact. NetApp focuses on providing a flexible and cost-effective DR solution, making it affordable for you to cover more of your application tiers under a single DR plan. Alternatives from other vendors focus on just the top 5% 10% of mission-critical applications and tend not to have cost-effective solutions for the other 90% 95% of business-critical applications. Organizations have traditionally viewed their DR investment as an expensive insurance premium against disasters. NetApp DR solutions have changed this equation by making it really easy to put the DR site to active business use offloading the production system for tape backups, application testing, and remote read access. NetApp delivers exceptional data availability with product simplicity, fast data recovery, storage resiliency, and affordable DR solutions that enable you to protect more of your applications for less Network Appliance, Inc. All rights reserved. Specifications subject to change without notice. NetApp, the Network Appliance logo, Data ONTAP, SnapManager, SnapMirror, SnapRestore, SnapVault, and SyncMirror are registered trademarks and Network Appliance, FlexClone, FlexVol, RAID-DP, and Snapshot are trademarks of Network Appliance, Inc. in the U.S. and other countries. Microsoft is a registered trademark of Microsoft Corporation. Oracle is a registered trademark of Oracle Corporation. All other brands or products are trademarks or registered trademarks of their respective holders and should be treated as such. 11