Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
On Wednesday 05 January 2011 13:35:28 Dale wrote: Jörg Schaible wrote: that approves my tests ... :-/ Had to boot this morning 5 times, since the root device switched arbitrarily between sde3 and sdg3 and I've chosen by bad luck always the wrong one. It seems there is also some timing involved regarding the initialization of the available devices ... sigh. - Jörg I had to reboot last night and was in my BIOS looking for other things but did notice this feature. I have a setting in my BIOS that tells it what drive to look for to boot first. It's above the part where you tell it to boot CDROM, hard drive, floppy, ZIP and other bootable things. You may want to check and see if you have the same thing. Mine is called hard disk boot priority. I'm not sure this will help but it couldn't hurt to check I guess. I also noticed something else that may not be related. I enabled AHCI a while back and noticed it will not boot from a CD/DVD when in that mode. I have to set it back to IDE for it to be able to boot from other than the hard drive. Maybe if you set yours to AHCI, it will skip the external stuff like USB? Dale, juust out of curiosity here. Do you have your CD/DVD drive attached using a SATA-cable? Or using an older IDE-cable? I use AHCI in my BIOS and can boot from CD/DVD. But my DVD-drive is a SATA- drive. -- Joost
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Had to boot this morning 5 times, since the root device switched arbitrarily between sde3 and sdg3 Try disabling CONFIG_SCSI_SCAN_ASYNC (Asynchronous SCSI scanning under SCSI options). While it is not a solution, this might somewhat reduce the randomness you are experiencing. andrea
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
J. Roeleveld wrote: Dale, juust out of curiosity here. Do you have your CD/DVD drive attached using a SATA-cable? Or using an older IDE-cable? I use AHCI in my BIOS and can boot from CD/DVD. But my DVD-drive is a SATA- drive. -- Joost My DVD drive is connected with a SATA cable. It was sort of odd that it did that and I plan to check into that more the next time I reboot. I made the changes so that I could boot from the DVD and when I was done booting from the DVD, I changed it back including the AHCI part. Dale :-) :-)
[gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Hi, Dale wrote: Alan McKinnon wrote: Apparently, though unproven, at 15:18 on Tuesday 04 January 2011, Stroller did opine thusly: I found numerous references to this syntax going back to 2005 or so, and some major distros seem to use it as the default way of describing root= to the kernel. http://www.linuxforums.org/forum/redhat-fedora-linux-help/23010-root- label- grub-conf.html http://linux.derkeiler.com/Mailing-Lists/RedHat/2005-01/0026.html However: http://old.nabble.com/Re%3A-Using--%22root%3DLABEL%3D%22-in- grub.conf-p 21909347.html http://tinyurl.com/2u4srg4 Stroller. All the major distros I've seen it on also use initrds though (rare in gentoo- land). I have no idea how it all works, I just know how to type it on a RHEL box. Elsewhere in the thread someone mentioned that this syntax relies on an initrd, and I suspect he may be correct. I tried using labels with the old grub a while back and it didn't work. Labels in fstab works fine tho. We may have to wait on the new grub to get finished. that approves my tests ... :-/ Had to boot this morning 5 times, since the root device switched arbitrarily between sde3 and sdg3 and I've chosen by bad luck always the wrong one. It seems there is also some timing involved regarding the initialization of the available devices ... sigh. - Jörg
[gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Hi Alex, Alex Schuster wrote: Dale writes: Alan McKinnon wrote: Apparently, though unproven, at 15:18 on Tuesday 04 January 2011, Stroller did opine thusly: I found numerous references to this syntax going back to 2005 or so, and some major distros seem to use it as the default way of describing root= to the kernel. http://www.linuxforums.org/forum/redhat-fedora-linux-help/23010-root- label- grub-conf.html http://linux.derkeiler.com/Mailing-Lists/RedHat/2005-01/0026.html However: http://old.nabble.com/Re%3A-Using--%22root%3DLABEL%3D%22-in- grub.conf-p 21909347.html http://tinyurl.com/2u4srg4 Stroller. All the major distros I've seen it on also use initrds though (rare in gentoo- land). I have no idea how it all works, I just know how to type it on a RHEL box. I am using an initrd, I need it since my root partition is encrypted. It's generated and copied to /boot with 'genkernel --install --luks --lvm all', but you have to have CLEAN=no in /etc/genkernel.conf or genkernel will create its own .config. Elsewhere in the thread someone mentioned that this syntax relies on an initrd, and I suspect he may be correct. And Stroller's 3rd link also does this. I tried using labels with the old grub a while back and it didn't work. Labels in fstab works fine tho. We may have to wait on the new grub to get finished I would be surprised if it had this feature. AFAIK grub is already done at this stage, the kernel has taken over. And I guess it does not know about the LABEL= syntax, and has no code to scan all devices for file system labels. I fear so, too. Grub finds the boot device properly, it's the kernel complaining about the value in the root option. With an initramfs, the kernel runs an init script which can do various stuff, like probing all devices for file system labels. I never had the need for an initrd. - Jörg
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Jörg Schaible wrote: that approves my tests ... :-/ Had to boot this morning 5 times, since the root device switched arbitrarily between sde3 and sdg3 and I've chosen by bad luck always the wrong one. It seems there is also some timing involved regarding the initialization of the available devices ... sigh. - Jörg I had to reboot last night and was in my BIOS looking for other things but did notice this feature. I have a setting in my BIOS that tells it what drive to look for to boot first. It's above the part where you tell it to boot CDROM, hard drive, floppy, ZIP and other bootable things. You may want to check and see if you have the same thing. Mine is called hard disk boot priority. I'm not sure this will help but it couldn't hurt to check I guess. I also noticed something else that may not be related. I enabled AHCI a while back and noticed it will not boot from a CD/DVD when in that mode. I have to set it back to IDE for it to be able to boot from other than the hard drive. Maybe if you set yours to AHCI, it will skip the external stuff like USB? I'm seriously pulling it out my butt here. I hope one of these will help. ;-) Dale :-) :-)
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Jörg Schaible writes: Alex Schuster wrote: I would be surprised if it had this feature. AFAIK grub is already done at this stage, the kernel has taken over. And I guess it does not know about the LABEL= syntax, and has no code to scan all devices for file system labels. I fear so, too. Grub finds the boot device properly, it's the kernel complaining about the value in the root option. With an initramfs, the kernel runs an init script which can do various stuff, like probing all devices for file system labels. I never had the need for an initrd. Now you do :) Wonko
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
On Wed, Jan 5, 2011 at 3:50 AM, Alex Schuster wo...@wonkology.org wrote: Jörg Schaible writes: Alex Schuster wrote: I would be surprised if it had this feature. AFAIK grub is already done at this stage, the kernel has taken over. And I guess it does not know about the LABEL= syntax, and has no code to scan all devices for file system labels. I fear so, too. Grub finds the boot device properly, it's the kernel complaining about the value in the root option. With an initramfs, the kernel runs an init script which can do various stuff, like probing all devices for file system labels. I never had the need for an initrd. Now you do :) Wonko Wonko, I did my first initramfs build this last week to get RAID6 working for /. It went well and I was impressed at how much I could debug in a shell before I got it working correctly. (Big issue for me - make sure you copy all the /dev/sdX stuff you are going to need into the initramfs, and make sure mdadm is built static.) QUESTION: What's the difference between initrd and initramfs in practice. As I understand it initramfs is the newer one. I assume that means it's preferred? Or are there times when someone wants to still use an initrd? Thanks, Mark
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
Apparently, though unproven, at 19:18 on Wednesday 05 January 2011, Mark Knecht did opine thusly: On Wed, Jan 5, 2011 at 3:50 AM, Alex Schuster wo...@wonkology.org wrote: Jörg Schaible writes: Alex Schuster wrote: I would be surprised if it had this feature. AFAIK grub is already done at this stage, the kernel has taken over. And I guess it does not know about the LABEL= syntax, and has no code to scan all devices for file system labels. I fear so, too. Grub finds the boot device properly, it's the kernel complaining about the value in the root option. With an initramfs, the kernel runs an init script which can do various stuff, like probing all devices for file system labels. I never had the need for an initrd. Now you do :) Wonko Wonko, I did my first initramfs build this last week to get RAID6 working for /. It went well and I was impressed at how much I could debug in a shell before I got it working correctly. (Big issue for me - make sure you copy all the /dev/sdX stuff you are going to need into the initramfs, and make sure mdadm is built static.) QUESTION: What's the difference between initrd and initramfs in practice. As I understand it initramfs is the newer one. I assume that means it's preferred? Or are there times when someone wants to still use an initrd? AFAIK, initramfs is the newer preferred one and it's either one or the other with initrd being seldom used these days if at all. Many people still call it initrd even if int's initramfs in use - sort of a slang thing -- alan dot mckinnon at gmail dot com
Re: [gentoo-user] Re: Re: Re: Changing boot device with 2.6.36
On Wed, Jan 5, 2011 at 12:09 PM, Alan McKinnon alan.mckin...@gmail.com wrote: SNIP AFAIK, initramfs is the newer preferred one and it's either one or the other with initrd being seldom used these days if at all. Many people still call it initrd even if int's initramfs in use - sort of a slang thing I suspected as much. I was calling it initrd until I started reading how to do one and found the new name. I have run from the idea of doing one liked a scared little child at a murder scene for the 10 years I've basically had Gentoo as my desktop PC. After a couple of hours of using it I've started to think maybe I should have one on every new system I do. After I got the rescue environment with busybox going I could see why mdadm couldn't start the RAID and knew how to fix it almost immediately. I was thinking about how much time I've wasted on new bring ups where it cannot sync the file system. Just being able to get around those sorts of problems would have likely saved me days of time over the last decade. Thanks! - Mark
