How to resolve escalating costs and administrative complexity in branch offices.
ENTERPRISE CHALLENGES
Large businesses continue to distribute themselves into branch offices to gain real-estate cost benefits, flexibility to hire personnel across disparate geographies, and more closely address their customers and partners. But the shift has them facing the potential IT cost and complexity challenges associated with managing local file servers and storage resources in growing numbers of distributed sites. Few organizations today can afford to employ local IT staff in tens, hundreds, or thousands of locations, as well as manage and back up the large amount of data stored locally.
Traditionally, adding a branch office means extra equipment to manage and data to secure and track. In addition, file sizes are generally increasing, in part because of the deployment of more sophisticated applications that take advantage of multimedia capabilities. Data storage requirements are also on the rise because of regulatory compliance mandates.
The compliance mandates, such as Sarbanes-Oxley, the Health Insurance Portability and Accountability Act (HIPAA), and the Gramm-Leach Bliley Act, require much closer auditing and record-keeping of network and data access than in the past. As such, they make managing multiple, redundant server and backup resources across the country or globe impractical. Rather, consolidating file and storage resources into the data center eases management, administration, cost, and compliance.
The difficulty is that the centralization of resources creates significant performance problems for remote users accessing centralized file and print services.
There are three primary reasons:
• WANs are slower than LANs.
• Long distances in the WAN add latency to file and print service requests.
• File service protocols are "chatty," often requiring hundreds or thousands of round-trip client/server message exchanges for even the most trivial operations. Chattiness adds extra latency to file service requests.
As a result, standard file access protocols perform poorly over the WAN. So how does the enterprise balance the need for centralized file and print service management with the traditionally high performance required in its branches?
BRANCH CONSOLIDATION WITHOUT COMPROMISE
Cisco® Wide-Area File Services (WAAS) software helps enterprises gain the benefits of centralized storage and contain costs while maintaining local file service performance for branch office users. Cisco WAAS enables the consolidation of branch office file servers and storage into central file servers or network-attached-storage (NAS) devices through the use of intelligent caching, proxy, and WAN transport optimization technologies, collectively known as Wide Area File Services (WAFS) technology. Additionally, Cisco WAAS enables print services to be managed from the WAAS device itself.
Deployed in the branch office's WAN edge networking equipment, these capabilities resolve the performance problems of users having to access file and print services over the latency-prone, bandwidth-constrained, and over-utilized WAN.
Cisco WAAS provides a local file service interface for the standard Common Internet File System (CIFS) and Network File System (NFS) file services. It also applies optimizations where appropriate to reduce the local site's dependence on the WAN for access to stored data.
In this way, Cisco WAAS addresses the enterprise branch office challenges of redundant equipment and management costs by removing the requirements for multiple, costly data components in every enterprise site. By centralizing resources while maintaining local file and print service performance, enterprises can dramatically reduce their branch office total cost of ownership (TCO). For example, they can eliminate redundant file and print servers, the licensing costs and management of server software and backup software, tape drives, cartridges, and cartridge shipping costs.
The use of Cisco WAAS also eliminates the administrative difficulties and tasks associated with dispersed local file servers. For example, IT staff no longer must battle general-purpose server operating system (OS) viruses and keep up with frequent OS patching across a multitude of sites. IT administrators can centrally manage file services such as usage quota, backups, disaster recovery, restores, access control, and security policies.
Cisco WAAS software also reduces TCO by enabling resource sharing. Rather than storing multiple copies of the same files across large numbers of locations that must be kept synchronized and secured, for example, Cisco WAAS makes it possible to keep a single copy of a file in the data center, thereby enabling global collaboration. In an environment with 50 branch offices, rather than requiring 51 silos for data protection (one in each branch, plus one in the data center), the enterprise requires just one data silo for the entire company in the data center. This eliminates the need to maintain multiple copies of files and the complex job of synchronizing files across sites.
Similarly, consider the benefits of shared storage resources: If 50 branches each need the same 100 gigabytes of information and each has a copy, the enterprise must invest in and support 5 terabytes of data storage capacity. Alternatively, with the 50 sites sharing one copy of the 100-gigabyte set of files, the enterprise realizes a 50-fold reduction in storage requirements.
These are among the reasons that many enterprises using the Cisco WAAS-based approach to centralized management have found that the payback on their investment in Cisco WAAS and associated hardware occurs in less than six months.
MAKING WAN PERFORMANCE LAN-LIKE
Cisco WAAS uses four basic capabilities to enable LAN-like file and print service performance in the WAN, while allowing file and storage resources to be consolidated and managed centrally in the data center:
• Protocol-specific optimization
• Intelligent caching
• Support for local print services
• Network layer optimization
These capabilities reside in Cisco WAAS software, which operates on a Cisco Wide Area Application Engine (WAE) at the branch. Available as a standalone appliance or as a network module for the Cisco Integrated Services Router (ISR), the Cisco WAE hardware platform with WAAS software consolidates the functions of multiple file and print server-related devices to reduce capital and operating expenditures. At the same time, it enables additional protection of data, which can be stored centrally in the data center where the enterprise IT personnel with the greatest experience in data protection are typically found.
Let's take a brief look at each Cisco WAAS capability.
• Protocol optimization-Cisco WAAS provides an intelligent interface for the CIFS and NIFS protocols in the branch office. File service signaling, non-critical messages, and chatter are terminated locally rather than across the latency-prone WAN, thereby dramatically improving performance.
• Intelligent caching-Cisco WAAS provides LAN-like read and write access to files stored in the data center file servers or NAS devices, using two forms of caching. Using data read caching, when a user opens a file, a copy is stored on the local device. From then on, with each request, Cisco WAAS checks to see if the data has changed; if it has not, the data is served as a local request with LAN-like performance. This setup not only helps minimize the amount of bandwidth consumed when accessing files, but also helps ensure that a stale file is never served.
Cisco WAAS does not require the entire file to be cached before information is served from a file. Read requests can be served from a file that is partially cached, assuming the requested segments are cached. Cisco WAAS can also read ahead within the file to increase the likelihood of future cache hits to enhance performance.
Using data write caching, if a user performs a write operation on the wire, the Cisco WAE checks the type of write operation. If it is the type that requires a commitment-for instance, if a user is saving and closing the file-the write operation propagates synchronously to ensure data integrity. If the write operation does not require an immediate commitment, the Cisco WAE applies safe write optimizations to improve application responsiveness.
Also, metadata such as file attributes and directory information is cached and served to requesting users locally to improve the user experience.
• Support for local print services-The Cisco WAAS implementation is unique in that it supports complete local Windows-compatible print services. Generally, eliminating a file server from a branch would also entail removing a print server. If the print server moves to the data center, print jobs would have to traverse the WAN, and print performance over the WAN is notoriously poor. Using printer-specific protocols and print formats, a 100-kilobyte print job might grow by an order of magnitude. By supporting local print services in its Cisco WAAS implementation,
Cisco enables consolidation of file servers without network operators having to suffer any print performance penalties.
• Network layer optimization-Anytime the CIFS or NIFS protocol does need to use the WAN, Cisco WAAS ensure that it does so efficiently. Data compression speeds throughput and reduces WAN congestion. Pipelining packs multiple messages into a common shipment to minimize the effect of WAN latency, and multiplexing enables multiple simultaneous conversations between edge and core devices. These functions all speed response times and overcome challenges in high-packet-loss WAN environments.
DEPLOYMENT AND MANAGEMENT
The Cisco WAAS solution involves deploying a Cisco WAE (in appliance or router module form factor) with WAAS software at each branch office, which provides application acceleration, WAN optimization, and local print services to provide LAN-like file access over the WAN. Another Cisco WAE with Cisco WAAS software resides at the data center and connects directly to file servers or NAS gateways to perform WAN optimized file requests on behalf of the remote WAAS deployment.
The Cisco WAAS Central Manager provides remote management and monitoring of all Cisco WAAS deployments. All configuration and administration for hundreds to thousands of nodes is performed from a central network operations center (NOC) using the Cisco WAAS Central Manager. The system organizes devices by common administrative units and enables centralized software distribution, upgrades, and rollbacks. The Cisco WAAS solution does not require installation of software on client workstations, file servers, or NAS devices. Fully transparent to the end user and the file server, Cisco WAAS integrates transparently into the existing network and file storage infrastructure.
SUMMARY AND CONCLUSIONS
Enterprises face significant cost, management, and security challenges as they attempt to scale file servers and storage capacity at each of an increasing number of branch sites. In addition, requirements for protecting data generated in branch offices are growing stricter because of regulatory compliance mandates. These factors have the potential to inflate an enterprise's branch office total cost of ownership, if each branch requires file servers, server software, and the management complexity associated with distributed data protection, recovery, and business continuance.
However, enterprises can gain the benefits of centralized file and print services, management, and resource sharing without compromising the performance expectations of the branch office users. Cisco WAAS solution-through its range of WAFS technologies-enables organizations to consolidate their file servers and storage from remote branch offices to the data center-where IT personnel and data protection infrastructure are readily available-for dramatic cost savings through the elimination of redundant equipment, storage space, software licenses, and compute resources. To ensure that this topology does not affect local user response times in each branch, Cisco WAAS overcomes WAN latency and bandwidth limitations by applying protocol- and network-specific optimizations to maintain application responsiveness while minimizing WAN utilization.
