Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Tormod Volden ha scritto: I reopen this bug so don't lose it off the radar. Giuseppe, do you have any comments here or on the Debian bug? I already cherry-picked your [f333bc0] (nodmraid boot option), but I have some doubts about [54b8d6f]. Reverting that change will break all broken configurations (and a lot of people are using dmraid only to handle the windows partition with this broken configuration) Luke, what do you think? Cheers, Giuseppe. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Tormod Volden ha scritto: With and /home on dmraid on two other disks /dev/sda and /dev/sdb I meant that /dev/sdaX and /dev/sdbX will be part of a dmraid array. But /dev/sdc which contains my root is not part of an array. Ok, then /dev/sdc will not be removed. Then Christian and other people with special set-ups can use this option to make sure dmraid is not run. Actually my two suggestions are pretty much the same as what Christian said in his original bug report. I don't consider that as a special set-ups. As I wrote some time ago, if you create mdraid out of the 2 raw partitions, you create mdraid meta data to the *partitions*. This is dead wrong, the raw disk partitions should never be used when the disks are part of a raid set. Cheers, Giuseppe. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Tormod Volden ha scritto: Ok, then /dev/sdc will not be removed. If I understand Use the -Z flag only if root partition is mountd in a dmraid array. correctly, the partitions on the two (dmraid member) disks /dev/sda and /dev/sdb will be exposed, in my example above. This is why I think this patch is wrong. In your example above, if your /dev/sdc is not part of an array, kernel will not remove it. If it happens this is a bug. If /dev/sda and /dev/sdb are part of an array, they will be removed, and this is *not* a bug, why it should be..? I don't consider that as a special set-ups. I agree that Christian's set-up is a broken one that we don't need to support. Anyway it could be handy sometimes to overrule any dmraid meta data left over on a disk and tell the system to not use dmraid. This is why I like nodmraid, which also would have solved Christian's problem. Yes I agree, this could be an interesting feature, but imho is not relevant with this issue. So maybe you could mark this bug invalid or wontfix, but I would not say it is Resolved by the above patch. Workaround (patch) that I added in the latest revision isn't elegant, but imho it fixed that issue. If it doesn't, please reopen this bug and write a testcase. Cheers, Giuseppe. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Tormod Volden ha scritto: In your example above, if your /dev/sdc is not part of an array, kernel will not remove it. If it happens this is a bug. If /dev/sda and /dev/sdb are part of an array, they will be removed, and this is *not* a bug, why it should be..? This is what I do not understand. The way I read the patch and its description, if this array is not used for root, -Z will not be used on it, so they will not be removed. Yes, apologies for the confusion, if this array is not used for root, -Z will not be used on it, otherwise my above sentence is true. Workaround (patch) that I added in the latest revision isn't elegant, but imho it fixed that issue. If it doesn't, please reopen this bug and write a testcase. I will leave to Christian to judge if this workaround fixes his issue. I am starting to wondering if you are talking about the issue in the linked Debian report, which might be somewhat different. I notice that Why are they different? They are the same issue, mdraid out of dmraid raw partitions or no-raid installation out of dmraid raw partitions. Other question: Why the special-casing of the root partition, shouldn't the same logic apply to all partitions? Yes, the logic is the same, but the special-casing prevents the boot failure when there is a wrong setup. Cheers, Giuseppe. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Tormod Volden ha scritto: I am not happy with this solution. What if I have / on one disk /dev/sdc and /home on dmraid on two other disks /dev/sda and /dev/sdb? I think my motherboard and BIOS would allow this. I would sure want /dev/sdaX and /dev/sdbX to be hidden by the -Z flag. if /dev/sdaX and /dev/sdbX aren't part of a dmraid array kernel will not remove them. What I think should be done instead: 1) make sure update-initramfs is triggered on dmraid package removal It is already triggered: http://git.debian.org/?p=users/derevko-guest/dmraid.git;a=blob;f=debian/dmraid.postrm 2) add for instance a boot option nodmraid which can be probed for in dmraid-activate And how this should fix this issue? Cheers, Giuseppe -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Yes, i understand that it's a driver for BIOS magic that i'd rather not use. When you create a RAID from the BIOS it does a RAID1 or whatever on the entire array using all the drives you select. You cant do a partial bios raid setup as this is illogical. Is there a usage scenario where this causes problems? It's running, i'm using it, and it appears to work just fine. I agree, it's an ugly hack, but so is BIOS raid... If it's a dangerous hack, how is this likely to manifest? It is much simpler to just use dmraid instead of mdadm, it will gather the raid setup from the bios without you having to do anything. The official ubuntu documentation begs to differ with respect to both ease and safety: from https://help.ubuntu.com/community/FakeRaidHowto: FakeRAID is not supported by Ubuntu. So it secures the system from data loss, but the system can nonetheless crash. Not entirely confidence-inspiring... -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Interesting, thanks for the info. Sorry to flog this to death. Online ubuntu docs with respect to dmraid are definitely somewhat scattered and of varying levels of authority. From a naive newer is better perspective, the page you mention was last edited 2008-08-06, long before jaunty went live, whereas the fakeraid howto was last edited 2009-07-03. Thanks again. I'll post details if anything terrible happens to my current config. On Wed, Jul 8, 2009 at 7:38 AM, danwood76danwoo...@gmail.com wrote: That wiki page is a little old: https://wiki.ubuntu.com/DmraidSupport -- Far better an approximate answer to the right question, which is often vague, than the exact answer to the wrong question, which can always be made precise -- j.w. tukey -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
I want to reiterate that the original bug was reported against the _alternate_ install cd. If i understand correctly, the alternate install cd is required to install using any raid functionality. The initramfs installed by the alternate cd included mdadm, which was unexpectedly difficult to remove. In my case, i had to use the livecd to rescue the system, since the livecd did not (in my case) automatically load dmraid, allowing me to manually mount my mdadm-generated root partition and modify the freshly installed system. A brief note as to *why* - I do not plan on reinstalling or altering windows (other than to shrink partitions), and i need to use mdadm under linux. I'm curious to hear evidence of configuration as unstable. thanks for all the feedback, christian -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
You cannot have mdadm and dmraid co-exist, unless the mdadm partitions and the dmraid array are on separate drives. YOu can only have one or the other. So if you have WIndows sitting on fakeraid/dmraid array, you install Ubuntu using the laternate CD, and when it asks for you to activate the SATA RAID array, you choose yes, and create partitions for filesystems as you would normally. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 392510] Re: Dual-boot install using mdadm root fails to boot
Just to reiterate, I achieved the desired results described in the original bug after extensive research, trial and error before i filed the bug. To get rid of dmraid you just don't install it. The live cd doesn't have the dmraid package preloaded Ok. But that's not at issue. The alternate install cd was used, which *does* install dmraid by default. See original bug. I'm sure getting rid of dmraid is as simple as un-installing it through apt and rebuilding the initramfs. Not true! Perhaps this is an upstream issue, but it's very unexpected behavior that apt-get remove dmraid does ***not*** purge dmraid from initramfs. Uninstall and reinstall of mdadm is required. See original bug for discussion, esp. link to debian bug. Also you could purge the fakeraid from the drives by clearing the metadata at the end of the disks and then dmraid wouldn't even load. Ok, but that defeats the goal stated in the original bug, since windows could not use its default configuration of fakeraid. I understand that the interaction between dmraid, mdadm, the 2 different install disks, initramfs, bios and windows is non-trivial, but none of the responses to date address the original bug, and some contain false assertions. -- Dual-boot install using mdadm root fails to boot https://bugs.launchpad.net/bugs/392510 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
