Wednesday, October 20, 2021

Running Linux in Windows 11

 Most people that know me, also knows how I really don't like working with Windows. I actually worked with Microsoft products already in the 1980s, so I haven't been able to stay away from them completely.

Developing MySQL on a Windows platform haven't been so easy since building MySQL on Windows is difficult and also there are a number of issues in running even the simple test suites of MySQL.

At the same time the world is full of developers with only Windows as their development platform. So when I read about the possibility to run Linux inside Windows 11 I thought it was time to test if development of RonDB could now be done on Windows.

My 9-year old laptop needed replacement, so I went ahead and found a nice Windows laptop at a fair price. I wanted to test the very latest developments that I could find in Windows 11. Since the laptop was delivered with Windows 10 I did an unusual thing, I wanted to upgrade the OS :)

This wasn't exactly easy, took a few hours, but eventually after upgrading Windows 10 a few times and searching for a Windows 11 download I eventually found such a one using Google on the Microsoft website. After a couple of upgrades I was at the latest Windows 11 release.

Installing Linux was quite easy, it was one simple command. I installed an Ubuntu variant.

Most of the installation went ok. The graphics installation didn't work, but the installation of terminal software was good enough to test at least the testing part. For development I use graphical Vim, so this needs to wait for a working version of the graphical parts of Linux (or using a Windows editor, but likely not since they tend to add extra line feeds on the line).

Downloading the RonDB git tree went fine. Compiling RonDB required installing a number of extra packages, but that is normal and will happen also in standard Linux (build essentials, cmake, openssl dev, ncurses, bison, ..).

Running the MTR test suite also went almost fine. I had to install zip and unzip as well for this to work.

Running the MTR test suite takes about an hour and here I found a few challenges. First I had to find the parallelism it could survive. I was hoping on parallelism of 12 (which in reality for RonDB means 6 parallel tests running). But in reality it was only stable with a parallelism of 6.

However since I wasn't sitting by the Windows laptop while the test was running the screen saver decided to interfere (although I had configured it to go into screen save mode after 4 hours). Unfortunately the screen saver decided that the Linux VM should be put to sleep and this meant that all test cases running when the screen saver hit in failed. Seems like this is a new issue in WSL 2 not existing in WSL 1.

However I think that I am still happy with what I saw. Running an operating system inside another and making it feel like Linux is a part of Windows isn't an easy task. So here I must give some kudos to the development team. So if they continue working on this integration I think that I am going to get good use of my new laptop.

I must admit that I don't fully understand how they have solved the issue of running Linux inside Windows. But it definitely looks like the Linux kernel makes use of Windows services to implement the Linux services. Running top in an idle system is interesting, there is only a few init processes and a bash process. So obviously all the Linux kernel processes are missing and presumably implemented inside Windows in some fashion.

The best part is that the Linux VM configuration isn't static. The Linux VM could make use of all 16 CPUs in the laptop, but it could also allow Windows to grab most of them. So obviously the scheduler can handle both Linux and Windows programs.

Memory-wise the Linux VM defaults to being able to grow to a maximum of 80% of the memory in the laptop. However in my case top in Linux constantly stated that it saw 13.5 GB of memory in a machine with 32 GB of memory. I saw some post on internet stating that Linux can return memory to Windows if it is no longer needed. Not sure I saw this, but it is a new feature, so feel confident it will be there eventually.

So at least working with RonDB on Windows 11 is going to be possible. How exactly this will pan out I will write about in future worklogs. At least it is now possible that I can do some development in Windows, it was more than 30 years ago I last had a development machine with a Microsoft OS, so to me, Linux on Windows is definitely making Windows as a platform a lot more interesting.

My development environments have shifted a bit over the years. It started with a mix of Microsoft OSs and Unix and some proprietary OSs in the 80s. In the 90s I was mostly working in Solaris on Sun workstations. Early 2000's I was working with Linux as development machine. But since 2003 I have been working mostly on Mac OS X (and of course lots of test machines on all sorts of platforms).