A curious case of memory dump diagnostic: How Stackify can cause troubles to your site

It’s been a while since my last blog post, and this time it will be fun time with windbg. One of DXC customers has been having problem with instances of their site hang and restart. We at Episerver takes the availability and performance of DXC sites very seriously, therefore I was asked to help diagnosing the problem. It’s something I’d like to do and to learn anyway, so game is on.

The golden standard for looking at the kind of those problems is still the tried and trusted Windbg. With the help from the Managed Services Engineer, I was able to access several memory dumps from the site. Most of them were taken when the site stalled, which is usually the most useful moment because it should contain the most critical piece of information why the stall happened.

Continue reading “A curious case of memory dump diagnostic: How Stackify can cause troubles to your site”

Debug .NET memory dump with WinDBG – crash course. Part 1

If you ask me what had I been doing the last two weeks – then the answer is I was pulling my hairs.  A customer had a problem with their site as the memory hiked up after catalog imports and stayed there “forever” – and in the end it slowed the site down. I jumped in and almost regretted that decision – had to spent days  messing around with WinDBG and memory dumps. In the end – I found the problem and it was fixed. A lot of hairs were loss in progress, but I learned something about WinDBG – and that’s what I’m sharing today.

WinDBG is probably the most famous tool for debugging stuffs on Windows. Out of the box, it only works with native applications, aka assembly and such – but lucky for us, there are plenty of extensions to allow it to work with .NET application. The “standard” SOS and more advanced extension SOSEX. SOS is included in WinDBG, while you can download SOSEX from here (for 64 bit) or here (for 32 bit) . Download the zip file and extract the dll somewhere.

WinDBG comes with the Windows SDK, not the standard .NET framework, so you’ll probably need to install it separately from here

Continue reading “Debug .NET memory dump with WinDBG – crash course. Part 1”