Category: Performance

Fix For Bit Rate Throttling W3WP Crashes

Over the Summer, we dove deep in to SharePoint 2010 for WCM when we re-launched our corporate website. As I mentioned the other day, I spent a decent amount of time looking at caching and some of the new supporting technologies, like Bit Rate Throttling, an IIS.NET extension to IIS 7.x – part of the IIS Media Services 3.0. package that also includes Smooth Streaming. Bit Rate Throttling is like when you watch a YouTube clip and it only buffers a short time in advance of what you’re watching, also known as Progressive Download. In Microsoft’s words, Bit Rate Throttling is…

“…an IIS 7.0 extension that meters the download speeds of media file types and data between a server and a client computer. The encoded bit rates of media file types such as Windows Media Video (WMV), MPEG-4 (MP4), and Adobe Flash Video, are automatically detected, and the rate at which those files are delivered to the client over HTTP are controlled according to the Bit Rate Throttling configuration.”

It basically saves you bandwidth by only transferring what you’ve watched plus a small, configurable buffer. Think about each user that starts watching a ten minute video but only watches one minute. In that time, they may have downloaded five minutes of content – quadrupling the bandwidth consumption unnecessarily. Bit Rate Throttling shares some user experience characteristics with Streaming Media, but it works on a normal web server over HTTP. It’s really quite a simple tool and I won’t devote space here to explaining it when the IIS.NET site already has some great content, including a brief introductory video. Definitely check it out.

So why am I writing about it?

Continue reading “Fix For Bit Rate Throttling W3WP Crashes”

BLOB Cache, HTTP 304 Results and F5/Refresh

A few months ago we launched a new website on SharePoint 2010. One of my main foci on the project was performance and caching is one of the most effective ways to achieve that for a WCM solution. We enabled Output, Object and BLOB caching,  configured exclusions as necessary and were quite pleased with the results, especially since issues with BLOB Caching in 2007 have been resolved in 2010.

A few weeks later I was demonstrating these approaches when it was pointed out that we were getting lots of 304 responses. They occurred with each request for a previously-downloaded BLOB Cached asset (more detail added below). Basically, I overlooked the max-age attribute in the BLOB Cache web.config settings. By default, this attribute isn’t present in the web.config file and I simply missed it. Adding this attribute eliminated the 304 results and the caching configuration was complete. Or so we thought.

Edit to provide more detail on the 304 status and Max-Age
A 304 response is a File Not Modified status (not an error), in this case indicating that the browser is making (potentially) surplus checks for each previously-downloaded BLOB Cached file. The max-age attribute gives the file a lifetime in the client’s browser cache in order to reduce these update checks. To be clear, the BLOB Cache stores large objects on web servers to reduce database traffic, but those objects can be served with a max-age attribute that will determine the object’s lifetime in the client’s browser cache. A max-age value of “14400” means that browsers will cache the file for four hours before checking for an update. This means that updates to BLOB Cached content may become stale if this value is set too high. A common value would be “86400” (24 hours) but we were satisfied with the balance at four hours. In our case, making this update has not yielded a perceptible increase in performance with the current levels of traffic, but it’s the sort of thing you want to set appropriately in order to optimise things and to allow the environment to scale.

Continue reading “BLOB Cache, HTTP 304 Results and F5/Refresh”

Hyper-V video issues fixed by Windows Server 2008 R2 SP1 Beta?

Recently we’ve been considering a hardware refresh for our developer/consultant/architect laptop build (on Windows Server 2008 R2 Standard with Hyper-V). After a fair amount of deliberation we decided to pilot a new model but stumbled massively at the first hurdle: when we enabled the Hyper-V role on a new Dell Latitude E6410 we got a blue screen. Further testing revealed that the graphics driver was at fault and the SVGA driver worked fine. However, the SVGA driver only has single monitor support. Back to the drawing board.

Continue reading “Hyper-V video issues fixed by Windows Server 2008 R2 SP1 Beta?”

Optimising the SharePoint 2010 IW Demo VM Part 2

Continuing on from Part 1, in this post I’ll discuss the Microsoft 2010 Information Worker Demo Exchange VM, the SahrePoint VM’s event logs and potential future improvements to the environment.

Exchange Server Reconfiguration

Tidying up the Exchange server is a much more straight-forward process. In fact, all of the changes that I made are network orientated per the network changes from the first post, so if you are not adding a second NIC or a second fixed IP address on the original internal NIC, these steps aren’t necessary.
Continue reading “Optimising the SharePoint 2010 IW Demo VM Part 2”

Optimising the SharePoint 2010 IW Demo VM Part 1

Around the time that Microsoft released the public beta of SharePoint 2010 they also released a demonstration virtual machine, known as the 2010 Information Worker Virtual Machine, which was updated to RTM in mid-June. This is a fantastic resource for demonstrating SharePoint 2010. The content and demonstration scenarios (including walk-throughs) represent a huge investment from Microsoft and it would be foolish not to at least evaluate these assets. Personally, I think it’s silly to reinvent this wheel.

Now the public beta trial is expiring and people are moving to the RTM build. It appears to be much improved, in that more of the product works in this version and a few niggles have been fixed now. However, it’s widely acknowledged that the resource requirements for this virtual machine are gargantuan due to the breadth of what it offers.
Continue reading “Optimising the SharePoint 2010 IW Demo VM Part 1”

SharePoint 2010 SEO Analysis with the IIS SEO Toolkit

The IIS.NET Search Engine Optimization (SEO) Toolkit provides a powerful analysis tool that can generate reports for web editors and can automatically generate sitemaps and robots.txt files as well. These reports not only provide insight in to page rank improvements but also help content editors identify missing/duplicate content and find broken links. This post provides an overview of how the tools can be used by content editors or web managers who do not have access to the server infrastructure and what you can expect to see when running an SEO Analysis against an out of the box SharePoint 2010 Publishing site. I will also review the server tools that generate sitemaps and robots.txt files.

Installing the SEO Toolkit

Although Remote Server Administration Tools can be installed on Windows Vista and Windows 7, I have produced the directions below on my Windows Server 2008 R2 desktop. The instructions should be fundamentally the same for any OS once IIS Manager is available locally, however it is installed. To be crystal clear, the SEO Toolkit can be used by anyone with Windows Vista, Windows 7, Windows Server 2008 or Windows Server 2008 R2. It is not a requirement to have access to the web server and it is not necessary to install IIS locally.

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Office Web App default cache size is 100 GB

Earlier today I noticed some fairly innocuous commentary in the Features that influence the size of content databases section of the Storage and SQL Server capacity planning and configuration (SharePoint Server 2010) TechNet guidance:

“If Office Web Apps are being used, the Office Web Apps cache can significantly affect the size of a content database. By default, the Office Web Apps cache is configured to be 100 GB. For more information about the size of the Office Web Apps cache, see Manage the Office Web Apps cache.”

100 GB? Surely that can’t be right. So I followed the link and found that:

The Microsoft Word Web App and Microsoft PowerPoint Web App generate a series of images to create a rendition of a document that is viewable in the browser. If Microsoft Silverlight 3 is installed, XAML is used to create the rendition. Creating the rendition can consume large amounts of computer resources. To reduce resource consumption, the Word Web App and PowerPoint Web App store the renditions in a cache, created as part of a SharePoint content database. Renditions in the cache are then used for future requests of a view of the same document. In an environment where most documents change infrequently, but are viewed regularly, maximizing the space dedicated to the cache or the expiration period, can improve performance and reduce resource consumption. In an environment where most documents frequently change, you can optimize performance by reducing the space that is dedicated to the cache, or by reducing the time documents are stored in the cache.

So… make sure to plan SQL database disk space accordingly (nb: this is an update to the original post – I originally thought this was front-end disk space). Also note that you can pin the cache to a specific site collection’s content database. Either reduce the cache size (instructions in that link above) and adjust according to performance needs or invest in SQL storage accordingly.

And don’t forget to plunder the enormous investments Microsoft are making in SharePoint 2010 documentation. It’s the only way you’ll find out about all of these considerations.

PDF iFilter performance benchmarks, in which FoxIt performs nearly 40x better than Adobe

I’m not usually keen on re-posting other blog entries here, but I think this is quite important. Jie Li from Microsoft has been releasing some good guidance on SharePoint 2010 recently. In his most recent posts he’s been looking at FoxIt’s PDF iFilter 2.0 and comparing performance against TET and Adobe. Both TET and FoxIt are optimised for multicore processors while Adobe will only use a single CPU. This has massive performance implications. In his tests a full crawl too 13 minutes with FoxIt versus 8 hours+ with Adobe. http://blogs.msdn.com/opal/archive/2010/02/09/pdf-ifilter-test-with-sharepoint-2010.aspx

Building a SharePoint 2007/2010 development environment – Part VI: Issues and Results

In the first five parts of this series I covered the project objectives and the system design, then turned my attention to the Hyper-V host image build, automated deployment and the guest virtual machine build. In this post I review some of the questions and issues we’ve encountered after a few months of working this way and some overall reflections on the approach. Continue reading “Building a SharePoint 2007/2010 development environment — Part VI: Issues and Results”

The definitive word on Hyper-V high-end graphics performance

The Microsoft virtualisation team are certainly taking community engagement and transparency seriously these days. I’m happy to report that Ben Armstrong (Virtual PC Guy) has posted the definitive summary of Hyper-V high-end graphics performance issues. He was the first person to discover the issue and has produced most of the guidance on it since. Key things to note:
  • It’s not an issue on processors with SLAT, but these are only just hitting the market in laptops in the near future
  • It’s not an issue with the SVGA driver
    • I’ve asked if the SVGA driver might ever offer multi-monitor support. He’s looking in to it. This might be a great compromise until processors with SLAT become ubiquitous
  • This same problem occurs in all native Hypervisors
    • Virtual PC and VMWare Workstation do not have the same problem but they are Type 2 hypervisors and do not offer the same performance as Hyper-V

So… there’s still no conclusive solution but it’s good to have the full context of the problem. For more background on why this matters for SharePoint see my previous post on the matter.