WAN accelerators and third-party tools overview (SharePoint Server 2010)
Published: October 18, 2011
This article describes WAN accelerators and third-party tools that can be used with SharePoint 2010 Products that are deployed in geographically distributed environments.
In a WAN environment, WAN accelerators and third-party tools can help to speed up communications between clients and servers or between server farms. More efficient communication provides the ability to work offline and synchronize content, replicate or synchronize content between farms, and consolidate management of multiple farms.
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Because each environment is different, we do not recommend specific partner solutions. Moreover, partner solutions address opportunities in different ways. Consequently, each solution has different strengths. It is important to evaluate each solution, depending on the specific needs of your environment and the relative strengths of the partner solution.
Many partners offer solutions to enhance or optimize SharePoint Server 2010 solutions. For an updated list of partners, see the SharePoint 2010 Partner web site (http://go.microsoft.com/fwlink/p/?LinkId=231024).
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WAN accelerators benefit intranet deployments. These solutions typically optimize traffic at several levels. First, WAN acceleration solutions compress network level packets and optimize the underlying protocol to reduce the raw traffic. Second, WAN accelerators optimize content by comparing content blocks against a history of recently sent blocks, which enables only differences to be sent instead of all the content. Third, application-aware devices optimize the application-level protocol which reduces the application chatter. Different partner solutions use different combinations of optimization techniques and algorithms.
WAN accelerators work in pairs. One device is in the data center next to the servers that are running SharePoint Server 2010, and another device is in the branch office or on a client device outside an office. Vendors claim 90% or more reduction in response time for second and successive requests over high-latency networks.
Important criteria to consider when you choose a network accelerator include the following:
How many concurrent connections can the solution handle?
Can you virtualize the solution or is it a physical device?
Can you centrally manage the solution?
Does the solution handle secure sockets layer Secure Sockets Layer (SSL) traffic
Is the solution application-aware; specifically, SharePoint Server, Common Internet File System (CIFS), and Server Message Block (SMB) aware?
Does the solution offer a component that clients can install for mobile workers? If this is the case, what types of clients does it support?
Example solutions include the following: Certeon, Cisco, Citrix, Packeteer, Riverbed, and F5.
Offloading and cache devices
While caching techniques within SharePoint 2010 Products can reduce traffic, partners that provide offloading and cache devices can help bridge the latency gap between the clients and servers.
If you are hosting a SharePoint site over the Internet and your goal is to optimize network traffic and reduce the number of requests that hit your servers, then offloading and cache devices can play a role. Different partners target solutions to optimize the process of hosting content that is exposed to the Internet. Strategies that are employed in this space include caching and related proprietary techniques, offloaded compression with varying algorithms, warm ups and pre-fetching, and various shopping cart techniques. Some partners excel at delivering content securely and efficiently to specific types of clients, such as public kiosks, computers in Internet cafes across the globe, or other small devices that are not well-connected.
Also in the Internet arena there are global caching, network-optimization routing techniques to reduce dropped packets. For example, to optimize network traffic some solutions send only the changes within client requests to the server. These types of solutions reduce WAN traffic and can also produce quicker page returns because the number of round-trip communications between the client and server or between other intermediary devices is reduced.
Similar to Microsoft Forefront Unified Access Gateway (UAG), some solutions provide offloaded or delegated authentication as a gateway for accessing information. These solutions add another layer of security. To address multiple requirements, look for products or solutions that provide a firewall, load balancing, and intelligence for offloading and caching. Expect to see even more consolidation of these types of features in the future.
Example solutions include the following: Cisco, F5. Microsoft: UAG Server, TMG Server.
Content delivery networks
A content delivery network (CDN) provides global caching and network optimization routing by building server farms in multiple locations around the world. User requests are routed to the closest server farm, which eliminates what might otherwise be a high latency connection back to a central location. The CDN provider can often provide detailed statistics about user response time based on location.
The server farms operate as caches. A central SharePoint farm, known as the “source” or “origin”, populates and refreshes the caches. It is possible to mix content types, so that the central SharePoint farm serves pages and documents, but the CDN serves images and media files. The cached content can either expire naturally based on an age setting, or a Web Service call to a CDN management endpoint can forcibly expire cached content.
CDNs typically host only anonymous content. However, even sites that host secured documents can benefit from a CDN if a significant portion of the traffic is composed of non-secured files such as images, scripts, style sheets, transforms, and other resource type files. The benefit should be compared to the cost because CDNs can be expensive, and they add administration complexity especially for the authoring process. For example, it can be difficult to resolve issues such as adding links to a wiki page that references an image that has not been published to a CDN or that is published as a different version.
Example solutions include the following: Akamai, Limelight, Level 3 Communications, and Microsoft Windows Azure.
Some partners focus on how to optimize the client experience, instead of on how to address the network and server infrastructure. Techniques such as pre-fetching, background synchronization, compression, ad blockers, and image filters can significantly reduce the time that is required to retrieve content on the Internet. This is especially true if text is the primary target and you can manage without images.
Several client applications enable users to synchronize with SharePoint sites automatically. After the client initially synchronizes with a site, the client application automatically caches the contents of the site on the client computer in the background or when the client is online. For example, when a user clicks a document, the document is already locally available and the user is not affected by WAN links. Similarly, when a user adds or updates a document, the client application deals with synchronizing the changes with the online site. These client applications typically manage any conflicts that arise and enable users to decide how to resolve conflicts.
Microsoft Outlook 2010 can synchronize a SharePoint library, contact list, task list, Project task list, and certain types of SharePoint external lists. Once you synchronize a library, the library is displayed as a folder in the SharePoint Lists section of the Outlook Navigation Pane. You can also take the libraries offline, work with the Office files in the library, bring them back online, and then synchronize the changes.
To provide a good offline experience across a WAN, Microsoft SharePoint Workspace 2010 enables real-time synchronization of desktop content with SharePoint documents and lists. Information workers can easily synchronize online and offline content with a designated SharePoint site or collaborate with external partners and offsite team members through shared workspaces. To minimize workload, updated packets are transmitted over the network instead of whole files or documents.
For more information, see Client solutions for WAN environments (SharePoint Server 2010).
Partners: Colligo Networks, Infonic, Microsoft Outlook 2010, SharePoint Workspace 2010, Microsoft Office Web Apps
Data replication, multi-master synchronization, and configuration administration
Slow WAN links between two offices or failure recovery requirements with a multi-master requirement might make replication necessary in deployment plans. SQL Server provides log shipping and database mirroring for data recovery or site failover. However, the failover site is either in warm standby or read-only mode. When you must have two separate server farms that both provide read/write access, then a partner replication solution is required.
Some partner solutions include a server cache similar to a WAN accelerator. The solutions continue to provide content from the cache at a remote site if a WAN link fails.
Other partners synchronize data in almost real-time or when sites are connected after extended periods of being disconnected. For example, a ship that arrives to a dock after being at sea can synchronize with a central site.
No multi-master synchronization solution can completely avoid update conflicts.
Consider these questions when you evaluate a solution.
How does the solution detect updates? For example, is it based on change logs, event receivers, or other?
Can the solution scope replication to specific sites or libraries?
How does the solution address update conflicts?
How is the replication traffic secured?
How much bandwidth is required for replication? For example, are only differences or complete files replicated? Can the bandwidth consumption be throttled?
Can the solution keep up with the predicted rate of updates over the network link?
How resilient is the solution to network errors or outages? How does the solution recover from network problem?
How is the solution managed? For example, does it use an integrated SharePoint user interface, Windows PowerShell, other?
A common need is to replicate user profile information between farms. User profile replication eliminates the requirement to import user profile data to remote farms. Instead, the profiles are imported to the central farm, and then profiles are replicated to the remote farms. The User Profile Replication Engine, which is part of the SharePoint Server 2010 Administration Toolkit, can perform either full or incremental user profile replication between two or more farms. For more information, see SharePoint 2010 Administration Toolkit (SharePoint Server 2010).
The product team has not yet tested publishing features of SharePoint Server 2010 in WAN environments. The publishing features might provide some value in publishing content from a central farm to read-only environments. However, without test results, we cannot provide specific guidance for this scenario.
Partner solutions include the following: Syntergy, AvePoint, Infonic. Microsoft: User Profile Replication Engine.
Multi-farm manageability and reporting
In global deployments that include multiple server farms, managing settings across the farms and sites can be challenging. Several partners offer tools that are designed to streamline the administration of configuration settings, permissions administration, effective user rights, and content elements such as master pages and content types. If you decide to deploy multiple server farms in your environment, consider partner tools that can help manage multiple farms and large volumes of sites.
If your deployment has several similarly configured farms, you can use a configuration-only backup and restore to replicate configuration settings between farms. You can restore a configuration backup to the same — or any other — server farm. When you restore a configuration, it will overwrite all settings in the farm that have values that are set within the configuration backup. For more information, see Copy configuration settings between farms (SharePoint Server 2010).
You can use Windows PowerShell 2.0 to manage SharePoint Server 2010. Windows PowerShell scripts can automate tasks and streamline administration. Windows PowerShell 2.0 introduces a new capability to manage your systems remotely from your desktop by using Windows Remote Management (WinRM). WinRM includes methods known as fan-out remoting and background jobs. After the necessary security is configured and WinRM is enabled on the remote servers by executing the Enable-PSRemoting cmdlet, you can execute script blocks on remote servers by using sessions and the Invoke-Command cmdlet. For more information, see Microsoft Press: Using Windows PowerShell to Perform and Automate Farm Administrative Tasks.
Partner solutions include the following: Quest Software, echoTechnology, idera, AvePoint, CorasWorks, CommVault, and Symantec.
Byte-level or hardware-based replication
Partners that provide hardware-based or byte-level replication make it very easy to fail over and to synchronize environments between data centers. If you implement a shared disk such as a storage area network (SAN), the shared disk can become a point of failure. Hardware vendors use various methods to provide redundant channels, redundant fiber, redundant disks, and various array configurations. Different solutions provide varying levels of fault tolerance.
If you want to eliminate hardware as the potential source for failure, evaluate Microsoft Cluster Service (MSCS). MSCS provides hardware-based fault tolerance. Software-based failover solutions such as SQL Server log shipping and SQL Server mirroring provide hardware fault tolerance, but failover is not automatic when you use it with SharePoint Server 2010.
In some cases, implementing a solution that provides replication at a lower level in the stack can address specific business needs. Byte-level replication, which creates a clone or a mirror of the primary environment, can also create a secondary environment to fail over to. Continuous byte-level replication can provide a means for either automatic or manual failover.
An important caution when you evaluate these types of replication solutions is to understand that server names, Web application names, and accounts are hard-coded in the configuration database. This means that a service that is replicated to a server that has a different name does not work. If the names of the server in the primary environment and replicated environment are the same, these types of solutions can work. Regardless of the solution, you must test a tool that provides replication outside the functionality of the application to make sure that the tool works in a failover environment.
Partner solutions include the following: Neverfail and Double-Take.
Solutions that are built into hardware, such as SAN-based replication, include the following: HP, EMC Centera, Dell, and Hitachi Data Systems.