On 11/17/2016 08:27 PM, Austin S. Hemmelgarn wrote: > On 2016-11-17 13:51, Hans van Kranenburg wrote: >> >> When generating a picture of a file system with multiple devices, >> boundaries between the separate devices are not visible now. >> >> If someone has a brilliant idea about how to do this without throwing >> out actual usage data... >> > The first thought that comes to mind for me is to make each device be a > different color, and otherwise obey the same intensity mapping > correlating to how much data is there. For example, if you've got a 3 > device FS, the parts of the image that correspond to device 1 would go > from 0x000000 to 0xFF0000, the parts for device 2 could be 0x000000 to > 0x00FF00, and the parts for device 3 could be 0x000000 to 0x0000FF. This > is of course not perfect (you can't tell what device each segment of > empty space corresponds to), but would probably cover most use cases. > (for example, with such a scheme, you could look at an image and tell > whether the data is relatively well distributed across all the devices > or you might need to re-balance).
"most use cases" -> what are those use cases? If you want to know how much total GiB or TiB is present on all devices, a simple btrfs fi show does suffice. Another option is to just write three images, one for each of the devices. :) Those are more easily compared. The first idea with color that I had was to use two different colors for data and metadata. When also using separate colors for devices, it might all together become a big mess really quickly, or, maybe a beautiful rainbow. But, the fun with visualizations of data is that you learn whether they just work(tm) or don't as soon as you see them. Mathematical or algorithmic beauty is not always a good recipe for beauty as seen by the human eye. So, let's gather a bunch of ideas which we can try out and then observe the result. Before doing so, I'm going to restructure the code a bit more so I can write another script in the same directory, just doing import heatmap and calling a few functions in there to quickly try stuff, bypassing the normal cli api. Also, the png writing handling is now done by some random png library that I found, which requires me to build (or copy/resize) an entire pixel grid in memory, explicitely listing all pixel values, which is a bit of a memory hog for bigger pictures, so I want to see if something can be done there also. -- Hans van Kranenburg -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
