Kent Overstreet - 04.03.24, 02:08:44 CET: > > This is not the same level of detail needed by a filesystem developer, > > and I _never_ said it was. I'm looking for the inforation > > needed/wanted by a SysAdmin when an end user comes whining about > > needing more space. And then being able to examine the system > > holistically to give them an answer. Which usually means "delete > > something!" *grin* > > 'bcachefs fs usage' needs to show _all_ disk accounting information > bcachefs has, because we need there to be one single tool that shows all > the information we have - that's this tool. > > If we're collecting information, it needs to be available. > > There will no doubt be switches and options for providing reduced forms, > but for now I'm mainly concerned with making sure all the information > that we have is there in a reasonably understandable way. >From a sysadmin view I totally get what John is writing. I know "btrfs filesystem usage" also shows a lot of information, but still with some learning it is quite understandable. At least I can explain it nicely enough in one of my Linux Performance Analysis & Tuning courses. Commands like "lspci" do not show all the information by default. You need to add "-v" even several times to show it all. So I am with you that it is good to have a tool that shows *all* the information. I am just not so sure whether showing *all* the information by default is wise. No one was asking for the lowest common denominator. But there is a balance between information that is useful in daily usage of BCacheFS and information that is more aimed at debugging purposes and filesystem developers. That "df -hT" is not really enough to understand what is going on in a filesystem like BCacheFS and BTRFS is clear. So what I'd argue for is a middle ground by default and adding more with "-v" or "--detail" or an option like that. In the end if I consider who will be wanting to use the information, my bet would be it would be over 95% sysadmins and Linux users at home. It would be less, I bet way less than 5% Linux filesystem developers. And that's generous. So "what target audience are you aiming at?" is an important question as well. What also improves the utility of the displayed information is explaining it. In a man page preferably. If there then is also a way to retrieve the information as JSON for something like that… it makes monitoring the usage state by 3rd party tools easier. Another approach would be something like "free -m" versus "cat /proc/ meminfo" and "cat /proc/vmstat". I.e. provide all the details via SysFS and a part of it by "bcachefs filesystem usage". You indeed asked for feedback about "bcachefs fs usage". So there you have it. As usual do with it what you want. You can even outright dismiss it without even considering it. But then I wonder why you asked for feedback to begin with. See, John just did what you asked for: John gave feedback. I planned to go into detail of your example output and tell you what I think about each part of what you propose and ask questions for deeper understanding. If you are open to at least consider the feedback, only consider, of course you can still decline everything and all of it after consideration, then I'd be willing to spend the time to do it. Best, -- Martin
