 All right, all right, is it using Debian installer again? I think you should give Python another chance. It's really a good Yes, I heard you had it. Thanks very much I've no idea where where when I lost it Yeah, thank you What is this work? All right, everyone If you look at a schedule, you will see that currently planned was last week's a news Unfortunately last night going to be here today What's this? It's already moment. Okay luckily Franz also immediately offered to do a whole replacement talk, which is where? I don't know. Okay So he was also offered to hold a replacement talk which he's going to do right now I'm sure you understand that this is done on short notice. So it might not be entirely As planned but anyway talk will be about persistent device naming and I think we already see what's happening if It's not going as Explained but in any case and if everyone please welcome Franz pop. Thank you very much Thank you so this is a subject that We in Debian have been avoiding for a little bit It's something we should solve But we haven't yet other distributions have worked on it But personally, I'm not really happy with the solution that are available at the moment So What is the problem? basically We used to use deaf HD a deaf SD a for our discs and In with all the kernels we could be reasonably sure that if you reboot the system The same disc would be behind deaf HD a as the previous boot So we have in in the FS tab Links to our partitions That that's a okay root is on deaf HD a five or something like that So as Walter said This is on very much improvised. So I hope you'll bear with me Yes That's going to catch me a few times So basically on my laptop if you look at deaf it the hard disk devices look like this As I say you cannot really rely on these devices being Persistent you cannot rely on them pointing to the same hard disk after different boots the most Obvious problem at the moment is when you have for example USB stick Insert the during your boot as That may turn up as the first disc instead of your real hard disk so how Should we work around it according to people who have developed you deaf? They have created for us these Beautiful Baths You basically have three alternatives that are supposed to be persistent you have the The path which is basically the the path to the hardware. So you see the PCI bus You have the ID, which is basically the identifier that the hard disk manufacturer put On the hard disk. That's the bottom one and of course you see the different partitions with both or you have the UU ID, I don't even know what you use ID stands for unique Something universal unique. Okay ID and that's something that's generated whenever you create a new file system so basically what we are supposed to do is put these huge strings in our FS step and put these huge strings in our grip bootline and Personally, I think that's not very user-friendly and These these strings don't mean anything to me to be honest and The other place where you would need them is for example in your smart Mon configuration file where you currently also have Slash dev SDA slash dev HDA so there's a lot of places where we would have to put these ugly Strings another problem with these is that they're not even completely persistent because if you look at the path if you have a satir disk then you can easily plug out or pull out the the plug to the to the to the main board and Put it in another one and then you will have the same disk on another path and So if you're using path at that moment In your FS step it will have changed if you use UU ID That would work. It would still be the same UU ID, but if you clone a disk Which is sometimes useful Then you would have the same UU ID on two discs then that would again confuse the system And by ID Part is of course the most stable Until you have to replace a disc so There's a lot of situations where even these Devices are not really persistent They cannot completely reliably point you to your data So how would that look if we look at This is how an FS step Mostly looks currently I here have swap partition on HDA 7 Buddhist HDA 1 Root on 5 and user on 6. This is totally Random example and if you're You may already be using UU ID for things like USB sticks to have them mounted on the same point always but That's basically the the only use currently Except if you already switched to the new model, of course So what would that become if we used one of the other options It would be become something like that which is Given that you the FS step everything has to be on one line It's become suddenly completely unmanageable in my view at least so the same would happen with UU ID or With both whatever you choose and One thing you may notice if I go back to the UU ID one Is that I haven't changed the swap why because swap doesn't have a UU ID? so You would have to use different Solutions for different types of devices. I Tried it on an installation Yesterday and I did not get a UU ID for my swap partition. Okay Okay You'd have doesn't use it. Okay. Well, I didn't see it in the path Okay, fine Well, one thing that really doesn't have you you ID is CD-ROM drive So you would probably use by path for that or something like that If you use UU ID, you don't have to do the dev disk by UU ID bit you can shorten that to This you can just use UU ID is which shortens is a little bit, but it's still way too long Now if you're going to read this this is not going to tell you If you run F disk or something, there's no relationship between what you see here And what you're going to see in in F disk. So some people have suggested to Do this when Is that I thought I had added? Comments here The idea was that above the UU ID line. You would have a comment Saying, okay, this is dev HDA 5 But I don't know if anybody can spot the obvious problem with that If HDA 5 is not persistent Then having the comment there is going to be totally useless right okay, so What I would personally like is if we could go back to having something simple like dev disk A1 or something like that. We probably cannot use HDA and SDA because those are tied to to to what the kernel does So we have to forget about them. They will they will always be there in dev and they will be basically only annoying because You cannot use them for anything sensible and the way I think we could solve this is by having a Separate step in new dev that generates these extra links to HD whatever and That should be done basically as the last step in the discovery So you would first have all these you'd have events coming up That's create the stable these persistent links that we have now and Then at the end when the queue is empty you would have an additional step that would create these new labels Let me see if I can show that and How it would work in this is this is just a wide ID that this has to be further developed What what would happen is that? You'd have would go looking in it is see somewhere it's you'd have somewhere for a file like this roughly like this Which would have both the path and the ID and for partitions the UU IDs that were known At the last boot so these files would be maintained automatically and then it would go searching and Say okay, I've now got I found a disk on this path on on this ID and It would say okay if everything matches then I can just Create the extra link disk disk a in this case and of course for the petitions with the number Appended now if you would Do the pull the SATA plug in this case and move it to another location to another bus the path would change Okay, so the path would change for from Well, it wouldn't be it would be a SATA path of course, but let's let's Let's let's make this one from master to slave for example So the path would change but the ID would stay the same So you could have heuristics in you deaf that would say Okay, if one thing matches, then maybe the disc was just moved Okay, and then it could update the changed path, but still keep the disc a the same with partitions if you If you repartition the device and for example you would delete the first partition And create two new partitions in the same place Then it would still find the you you IDs for the other partitions So it could Assign the same numbers even though the partitions themselves have been renumbered and Well, the reason this has to this would have to happen as a last step in you in you deaf is Because you're basically want all your devices detected because before you go doing this heuristic step So that's when there are Changes in conflicts you have all the information available to make a decision on What the new past should be I? Think this would not only work for hardest but also for Network interfaces For example for Even at zero you could have something like that you could have The hardware address and I'm pretty sure that I added the the path Below that as well At some point so it also has a PCI path my my my nick So if you then pull out a nick any certain new one with current you diff it would get a new Number it would it Ethan at zero would no longer be there. You would get either net one because it matches on the purely on the MAC address at the moment But if you had this system You could have heuristic say, okay Ethan at zero is gone. It's no longer in the system But in the same hardware slot, I've got a new nick So let's just assume that that's a replacement nick and assign the same Device Name I Also think that it would be useful to have user configurable options So that in some case you could say okay, even though this nick may disappear sometimes I know it will come back. So even if it disappears, please keep this configuration like this. Please keep this Name reserved for that nick so it it would be Fairly flexible I think So any thoughts about this? Rico About system labels. That's an option too. It's something that Fedora uses I think and Others the problem with that is that if you have a label root And a label us are and you want to install two operating systems on the same hard disk Then you're very likely to get conflicting labels You get you if you do a new installation Yes Yes, so you would have roots one and root two and root three and whatever The whole name Yes, so Labels is is not the answer either And and the nice thing about having something simple as disk a is that we could then also put that in all the default configuration files like For smart model and whatever What it would do in case of cloning is probably detect that there was a conflict like that and Either refuse to continue or just select one disk and Then probably if you have cloned then you would probably have Still have the ideas on the old path as well as on a new path and then it would prefer the one on the old path situation of having when something strange happens then Let's talk to figure out what to do I mean if I'm maintaining a system and I would like that Well, I choose to do it by say PCI slot ID and I know if I Move it to another PCI slot then I'll have to change it Mm-hmm Just probably but as I said, this is a very wild idea. This is in its really infancy stage I For power uses it does work. Yes, I agree I have a death disk a whatever and then it's in links to death by you you ID How does your system actually improve on that and Do you actually want to assume that if I take out my hard drive and I plug it in somewhere else that I don't have to make any Changes to the root file system Okay, I don't I don't see how that is Actually in motivation So how do you create those sim links at the moment? Manually, yeah, okay, and I put in a new hard drive. I know I have to change those. Okay Well, that's an option as well of course the thing that I'm of course coming from the background of the installer Where we have to solve this in some way and we have to solve it in a way that makes it work for New users and experienced Linux people This is But I'm just asking because I want you to think about I'm sure you have The real problem at the moment is that I Totally hate the idea of having these you you IDs and whatever in the FS step. So I'm looking for some kind of solution to that Creating links manually is not something that's going to Work in an installation. It's not going to to work for people who are not power users The existing Links that we have now you you ID and whatever are also created automatically. So I don't see a problem with creating another Additional link automatically And they actually don't have the path in there. There's only them. I know yes Why not just do exactly the same for this like your deaf aid SDA will always be deaf SDA Or it will always be this a like, you know Have been the actual file, and then you have death disks that I should be using slash SDA the problem is that as I explained earlier with with the internet case It doesn't work if you replace an ethernet card. It's a different card. It will get eaten at one Define my my laptop actually has LVM on it. I didn't use these examples, but LVM also has long paths, but at least they're humanly readable because Yes, so That's a Good question. I haven't solved that one yet And I think it's going to be a very hard one because if you look at the grub device file that still has The old style device names in it. I have no idea how to to solve that one For for the bootloader it's it's it's probably going to be an unsolved. Yes Yes Yes, so I'm I'm so trying to solve a part of the problem here But I agree that bootloader is is another issue The thing with bull already of course is that if you're going to Change disks and you're your boot is you're going to have problem anyway because you also have to tell your bios to to look for another disk And I think you will always have to make manual changes there the case I'm thinking of more is System with melt disks where you you swap out One disk and replace by another and not necessarily your boot disk That means a lot of us want to Solve again from an USB stick and I see a lot of people with Around and you can install began with The stick but at the first reboot you'll have to manually change once twice The path because during the installation the USB stick was assigned A and so your heart is going to be then you recruit with installation stick removed and Doesn't do any more because the heart is being as a instead of what it was during solution Which was so I'd really like you to find a solution for that Getting more and more common to install from I think I think we're out of time if anybody is Interested in pursuing this then please contact me I will probably set up a wiki page about this or something to to start discussion But I just wanted to throw this in the group