IT organizations are increasingly faced with the challenge of maintaining an always-on infrastructure, which requires data to be fully protected and accessible under any circumstances. IT organizations also are challenged to keep backup copies of data to facilitate recovery for everything from the desktop to high-end application servers. Furthermore, many organizations face pressure from regulatory bodies that require audits to make sure that information is protected to maintain industry or government compliance. With Cisco® Wide Area Application Services (WAAS), Cisco Systems® provides a solution that allows IT organizations to simplify server and storage infrastructure while improving performance for data-protection applications.
SERVER AND STORAGE CONSOLIDATION
Simplifying server and storage infrastructure is not an easy task. With a growing base of remote users who require specific service levels and performance to maintain productivity, simply removing servers and storage from remote offices and centralizing them in the data center is not a feasible solution. Furthermore, WANs are already heavily used, and the burden associated with simply consolidating servers and storage could overrun the remaining capacity. To meet these challenges, many IT organizations have been deploying costly, difficult-to-manage distributed server and storage infrastructure, as shown in Figure 1.
Figure 1. Costly and Difficult-to-Manage Server and Storage Infrastructure
Cisco WAAS provides a solution that both allows consolidation of distributed servers and storage and improves the performance of applications that are already centralized while minimizing the amount of WAN bandwidth consumption required to support remote-office applications. Cisco WAAS couples application acceleration and WAN optimization capabilities so that remote-office workers can access centralized servers, storage, and application infrastructure with LAN-like performance. Its features include the following:
• Application-specific acceleration-By applying acceleration to specific application protocols, Cisco WAAS can effectively overcome the limitations of application operation in WAN environments, such as bandwidth usage and application-layer latency. Cisco WAAS employs a variety of features for application-specific acceleration, including read ahead, message prediction, safe data caching, and operation batching to provide LAN-like application performance over the WAN.
• Advanced compression-Cisco WAAS employs two forms of advanced compression to minimize the bandwidth consumed on the WAN. Cisco WAAS Data Redundancy Elimination (DRE) allows Cisco Wide Area Application Engine (WAE) Appliances to store application-independent blocks of data found in TCP traffic and use them to reduce the need to send the same data twice within the compression history, providing up to 100:1 compression. Persistent Lempel-Ziv (LZ) compression is applied to further reduce bandwidth consumption and provides up to an additional 5:1 compression for data in transit, even data that has been optimized by DRE. With Cisco WAAS, WAN bandwidth is preserved and consumption is minimized, thereby improving application throughput and performance.
• Transport optimizations-Cisco WAAS provides optimizations for TCP with a suite of features called Cisco WAAS Transport Flow Optimization (TFO). TFO improves TCP performance and efficiency in WAN environments. By transparently scaling TCP windows and using intelligent congestion-management algorithms, Cisco WAAS helps TCP perform more efficiently and effectively over the WAN, improving application performance.
Cisco WAAS facilitates consolidation of server and storage infrastructure, resulting in fewer data silos that require protection. With fewer silos, less remote-office hardware, software, and management is required, thereby reducing costs associated with maintenance of data protection in remote sites. Furthermore, servers and storage consolidated in the data center, as shown in Figure 2, can be managed by the data center staff, reducing costs and time associated with remote-office IT staff.
Figure 2. Centralized Server and Storage Infrastructure Using Cisco WAAS
OPTIMIZATIONS FOR BACKUP OVER WAN
To reduce costs associated with remote offices and remote data centers, many IT organizations have begun to consolidate backup infrastructure in the data center and perform backup and restore operations on the existing WAN, as shown in Figure 3.
Figure 3. Backup over WAN
When backup is performed over a WAN, data protection infrastructure such as backup servers, tape drives, media, tape libraries, and potentially even costly offsite vaulting is not required in remote offices. However, because of WAN conditions such as bandwidth, latency, and packet loss, backup and restore performance over a WAN is much poorer than when backup is performed over a LAN to a nearby backup server. Cisco WAAS addresses these challenges through application-specific acceleration and WAN optimization functions to achieve high-performance backup and restore operations over the WAN. Cisco WAAS supports commonly used backup applications, including the following:
• CommVault: Galaxy
• Computer Associates: BrightStor
• EMC: Legato Networker
• IBM: Tivoli Storage Manager (TSM)
• Microsoft: NTBackup
• Symantec: Veritas BackupExec and Veritas NetBackup
Figure 4 shows how powerful Cisco WAAS optimizations are, comparing an unoptimized backup and restore operation over a WAN to an optimized backup and restore operation using Microsoft NTBackup with Office data files, images, and executables.
Figure 4. Backup over WAN Performance Improvement with Cisco WAAS
Figure 5. Restore over WAN Performance Improvement with Cisco WAAS
With Cisco WAAS deployed, backup and restore performance over the WAN is significantly improved, reducing backup timeframes and the amount of time necessary to restore data to a remote client workstation or server. Cisco WAAS TFO helps ensure that backup and restore operations perform well over the WAN by overcoming TCP performance challenges. DRE and persistent LZ compression help ensure that redundant data (such as files that have only partially changed) does not consume precious WAN bandwidth, and that all data transferred is compressed to minimize bandwidth usage. For backup software that uses the Common Internet File System (CIFS) protocol, additional protocol-specific acceleration mechanisms such as read ahead, pipelining, multiplexing, and prediction are employed to improve throughput and overcome WAN latency. With these optimizations, Cisco WAAS facilitates the centralization of costly data-protection infrastructure in the data center, removing it from remote offices, while maintaining backup and restore performance.
OPTIMIZATIONS FOR DATA REPLICATION
As data storage capacity continues to grow and enterprises move toward an always-on business model, many organizations struggle to continuously replicate data to provide business continuity, facilitate disaster recovery, and maintain regulatory compliance. Data replication is commonly deployed using one or more of the following mechanisms, shown in Figure 6:
• Host-based replication-Software installed directly on servers to replicate data to a distant server
• Network-attached-storage (NAS) device replication-Snapshot and replication functions from one NAS device to a distant NAS device, typically performed on a virtual server, volume, or file system
• Array-based replication-Replication of block data from one disk array to another disk array using a native Ethernet IP interface
• Fabric-based replication-Replication of block data from one disk array to another disk array using native replication tools, fabric-based replication services, or fabric-attached appliances that use TCP/IP as an interconnect
Figure 6. Common Data Replication Implementations
Cisco WAAS provides the foundation to improve the performance of many data replication applications and reduce the amount of time necessary to replicate data. Cisco WAAS provides optimizations for the data-replication scenarios listed previously and is compatible with data-replication products and technologies, including the following:
• EMC: Synchronous Remote Data Facility (SRDF), SANcopy, SnapSure, and IP Replicator
• HDS: TrueCopy
• Hewlett-Packard: Continuous Access (CA)
• IBM: Peer-to-Peer Remote Copy (PPRC) and Tivoli Continuous Data Protection (CDP) for Files
• Network Appliances: SnapMirror
• Symantec: Veritas Volume Replicator
• Other Connectivity over TCP/IP: Fibre Channel over IP (FCIP), Internet Fibre Channel Protocol (iFCP), and Internet Small Computer System Interface (iSCSI)
As shown in Figure 7, Cisco WAAS can be integrated into many data-replication environments and is configured by default to provide full optimization for such traffic, including elimination of repeated data patterns found in transmission, persistent LZ compression, and optimizations to improve throughput by overcoming TCP limitations. Cisco WAAS can also be configured for environments with higher levels of bandwidth so that replication applications can make better use of available WAN capacity.
Figure 7. Cisco WAAS Integrates Seamlessly into Data Replication Environments
• Asynchronous replication over WAN links with DS-3 capacity or less-Cisco WAAS provides full optimization, includingDRE, persistent LZ compression, and TFO,, to minimize bandwidth consumption and help replication applications more effectively and efficiently use available WAN capacity. As shown in Figure 8, Cisco WAAS can dramatically improve the throughput for such applications. In this example, a 1-GB volume stored on a NetApp NAS device is replicated over a T3 (45-Mbps) line with 80 ms of latency. This volume contains data from multiple file formats, including Office data files, images, compressed files, and executables.
Figure 8. Data Replication Performance over WAN Improvement with Cisco WAAS
• Asynchronous or synchronous replication over WAN links with greater than DS-3 capacity-Cisco WAAS can be configured to provide TFO to help replication applications make better use of available WAN capacity and overcome performance challenges associated with packet loss and latency on high-speed links such as OC-3 or OC-12. As shown in Figure 9, Cisco WAAS provides the TCP optimization capabilities necessary to help applications such as data replication make full use of available WAN capacity.
Figure 9. Full Use of High-Bandwidth Links by Data Replication and Other Applications with Cisco WAAS
SUMMARY
Enterprise IT organizations are challenged to control costs, facilitate data availability and recoverability, and use technology to help enterprises overcome potential disasters. By employing the robust application acceleration and WAN optimization capabilities of Cisco WAAS, IT organizations can achieve server and storage consolidation, thereby improving data protection and management. With fewer servers and data silos to protect, organizations can more effectively implement disaster-recovery and business-continuance technologies and procedures. Cisco WAAS can also optimize data protection applications such as backup over WAN and data replication to improve performance and reduce consumption of valuable WAN bandwidth.
