[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-01, Grant Edwards grant.b.edwa...@gmail.com wrote: I've just recently run into a problem where sometimes when a machine boots, the kernel can't find init. This appears to be because my grub configuration line says root=/dev/sda5 and _sometimes_ the drive that contains my root partition is sdb instead of sda. AFAICT, for the past 30 years the linux kernel was 100% consistent in the order that hard drives were labelled -- but recently that has seems to have changed. I still haven't figured out why my drives suddenly started getting discovered in varying orders. I think that the SATA drives are always in the same order with respect to each other, but sometimes the external firewire drive gets discovered before the SATA drives and sometimes after the SATA drives. It looks like my options are: 1) Keep hitting the reset button until it works. 2) Unplug or power down the firewire drive when booting. 3) Set up an initrd for the sole purpose of finding the actual root parition via filesystem label. [I find this idea rather offensive.] 4) Build the firewire drive as a module instead of building it into the kernel. That would delay the discovery of the firewire drive until after root has been mounted. 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. 6) Fix the kernel so it can find root by looking at filesystem labels. Number 6 (fixing the kernel) is The Right Thing To Do(tm), but it's a bit out of scope for the momement. The early code in the kernel obviously knows how to read partition tables and also knows about the relevent file system, so I'm a bit baffled why it can't look at the file system label. Changing the firewire driver to be a module is probably the simplest solution, but it's a kludgy work-around for what is, in my opinion, a kernel bug: if you are going to require people to specify an absolute disk drive index for the root partition, then you'd better index drives in a consistent order from one boot to the next. Switching to a GPT partition table sounds like the cleanest solution, but I need to figure out if the grub (legacy) ebuild includes GPT support or not. I know it's supported by grub2, but I don't really feel like switching to grub2 ATM. -- Grant Edwards grant.b.edwardsYow! But was he mature at enough last night at the gmail.comlesbian masquerade?
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
2013/7/2 Grant Edwards grant.b.edwa...@gmail.com On 2013-07-01, Grant Edwards grant.b.edwa...@gmail.com wrote: I've just recently run into a problem where sometimes when a machine boots, the kernel can't find init. This appears to be because my grub configuration line says root=/dev/sda5 and _sometimes_ the drive that contains my root partition is sdb instead of sda. AFAICT, for the past 30 years the linux kernel was 100% consistent in the order that hard drives were labelled -- but recently that has seems to have changed. I still haven't figured out why my drives suddenly started getting discovered in varying orders. I think that the SATA drives are always in the same order with respect to each other, but sometimes the external firewire drive gets discovered before the SATA drives and sometimes after the SATA drives. It looks like my options are: 1) Keep hitting the reset button until it works. 2) Unplug or power down the firewire drive when booting. 3) Set up an initrd for the sole purpose of finding the actual root parition via filesystem label. [I find this idea rather offensive.] 4) Build the firewire drive as a module instead of building it into the kernel. That would delay the discovery of the firewire drive until after root has been mounted. 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. 6) Fix the kernel so it can find root by looking at filesystem labels. Number 6 (fixing the kernel) is The Right Thing To Do(tm), but it's a bit out of scope for the momement. The early code in the kernel obviously knows how to read partition tables and also knows about the relevent file system, so I'm a bit baffled why it can't look at the file system label. Changing the firewire driver to be a module is probably the simplest solution, but it's a kludgy work-around for what is, in my opinion, a kernel bug: if you are going to require people to specify an absolute disk drive index for the root partition, then you'd better index drives in a consistent order from one boot to the next. Switching to a GPT partition table sounds like the cleanest solution, but I need to figure out if the grub (legacy) ebuild includes GPT support or not. I know it's supported by grub2, but I don't really feel like switching to grub2 ATM. -- Grant Edwards grant.b.edwardsYow! But was he mature at enough last night at the gmail.comlesbian masquerade? -- Mit freundlichen Grüßen / Best regards Randolph Maaßen
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
2013/7/2 Grant Edwards grant.b.edwa...@gmail.com: It looks like my options are: snip 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. Switching to a GPT partition table sounds like the cleanest solution, but I need to figure out if the grub (legacy) ebuild includes GPT support or not. I know it's supported by grub2, but I don't really feel like switching to grub2 ATM. I'm not exactly sure about your system's setup, but msdos partition tables can also hold partition UUIDs, which can be seen by running blkid. So, such a solution does not necessarily imply a GPT-based setup... you can experiment with it a bit, having fun tweaking kernel parameters :)
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On 07/02/2013 07:23 AM, Grant Edwards wrote: On 2013-07-01, Grant Edwards grant.b.edwa...@gmail.com wrote: 2) Unplug or power down the firewire drive when booting. I had this problem on my Intel motherboard, and found out you can disable booting from external drives. Boot to removable devices or similar in the BIOS. Failing that, changing the boot order so that the firewire/USB device is at the very end of the boot list may help your situation. Number 6 (fixing the kernel) is The Right Thing To Do(tm), but it's a bit out of scope for the momement. The early code in the kernel obviously knows how to read partition tables and also knows about the relevent file system, so I'm a bit baffled why it can't look at the file system label. Is CONFIG_EDD set? CONFIG_EDD: Say Y or M here if you want to enable BIOS Enhanced Disk Drive Services real mode BIOS calls to determine which disk BIOS tries boot from. This information is then exported via sysfs. Dan
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Randolph Maa?en r.maasse...@gmail.com wrote: 2013/7/2 Grant Edwards grant.b.edwa...@gmail.com It looks like my options are: [...] 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. And you can pass those values to the kernel via the root= parameter? -- Grant Edwards grant.b.edwardsYow! NEWARK has been at REZONED!! DES MOINES has gmail.combeen REZONED!!
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
2013/7/2 Grant Edwards grant.b.edwa...@gmail.com On 2013-07-02, Randolph Maa?en r.maasse...@gmail.com wrote: 2013/7/2 Grant Edwards grant.b.edwa...@gmail.com It looks like my options are: [...] 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. And you can pass those values to the kernel via the root= parameter? Yep. The G in GPT just means that the type of the partition is stored as GUID/UUID. The partition ID is a separate value. -- Grant Edwards grant.b.edwardsYow! NEWARK has been at REZONED!! DES MOINES has gmail.combeen REZONED!! -- Mit freundlichen Grüßen / Best regards Randolph Maaßen
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, Jul 02, 2013 at 02:42:15PM +, Grant Edwards wrote: You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. And you can pass those values to the kernel via the root= parameter? That still requires an initrd/initramfs, iirc. -- Happy Penguin Computers ') 126 Fenco Drive ( \ Tupelo, MS 38801 ^^ supp...@happypenguincomputers.com 662-269-2706 662-205-6424 http://happypenguincomputers.com/ A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail? Don't top-post: http://en.wikipedia.org/wiki/Top_post#Top-posting
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Daniel Frey djqf...@gmail.com wrote: On 07/02/2013 07:23 AM, Grant Edwards wrote: On 2013-07-01, Grant Edwards grant.b.edwa...@gmail.com wrote: 2) Unplug or power down the firewire drive when booting. I had this problem on my Intel motherboard, and found out you can disable booting from external drives. Boot to removable devices or similar in the BIOS. Failing that, changing the boot order so that the firewire/USB device is at the very end of the boot list may help your situation. The problem isn't that the BIOS is booting the wrong drive. The BIOS is booting the correct drive, grub is starting, grub is loading the correct kernel. When the _kernel_ runs it (sometimes) identifies disk drives in the wrong order and tries to mount the root directory from the wrong drive. Number 6 (fixing the kernel) is The Right Thing To Do(tm), but it's a bit out of scope for the momement. The early code in the kernel obviously knows how to read partition tables and also knows about the relevent file system, so I'm a bit baffled why it can't look at the file system label. Is CONFIG_EDD set? CONFIG_EDD: Say Y or M here if you want to enable BIOS Enhanced Disk Drive Services real mode BIOS calls to determine which disk BIOS tries boot from. This information is then exported via sysfs. This has nothing to do with what disk drive the BIOS tries to boot from (there's no problem with that). -- Grant Edwards grant.b.edwardsYow! I'm wearing PAMPERS!! at gmail.com
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Bruce Hill da...@happypenguincomputers.com wrote: On Tue, Jul 02, 2013 at 02:42:15PM +, Grant Edwards wrote: You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. And you can pass those values to the kernel via the root= parameter? That still requires an initrd/initramfs, iirc. The PARTUUID= parition specifier format is handled directly by kernel code, so I don't see why it should require an initrd (unless the UUID values for MBR partitions aren't actually something the kernel knows about and are something made up from whole cloth by the blkid program) -- Grant Edwards grant.b.edwardsYow! ... I have read the at INSTRUCTIONS ... gmail.com
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, 2 Jul 2013 15:16:15 + (UTC), Grant Edwards wrote: The PARTUUID= parition specifier format is handled directly by kernel code, so I don't see why it should require an initrd (unless the UUID values for MBR partitions aren't actually something the kernel knows about and are something made up from whole cloth by the blkid program) MBRs don't have PARTUUIDs do they? Don't confuse them with filesystem UUIDs as used in fstab. -- Neil Bothwick Oops. My brain just hit a bad sector. signature.asc Description: PGP signature
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, 2 Jul 2013 15:09:28 + (UTC), Grant Edwards wrote: I had this problem on my Intel motherboard, and found out you can disable booting from external drives. Boot to removable devices or similar in the BIOS. Failing that, changing the boot order so that the firewire/USB device is at the very end of the boot list may help your situation. The problem isn't that the BIOS is booting the wrong drive. The BIOS is booting the correct drive, grub is starting, grub is loading the correct kernel. When the _kernel_ runs it (sometimes) identifies disk drives in the wrong order and tries to mount the root directory from the wrong drive. And the BIOS order can affect the order in which the kernel sees the drives, so it is worth trying. I'd go for the firewire-as-a-module approach and add the module to /etc/conf.d/modules to make sure it is loaded ASAP. Yes, it is a kludge, but it is the simplest solution from a practical POV. -- Neil Bothwick Processor: (n.) a device for converting sense to nonsense at the speed of electricity, or (rarely) the reverse. signature.asc Description: PGP signature
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Randolph Maa?en r.maasse...@gmail.com wrote: 2013/7/2 Grant Edwards grant.b.edwa...@gmail.com I still haven't figured out why my drives suddenly started getting discovered in varying orders. [...] It looks like my options are: [...] 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. All the references Google can find for me say that you have to use a GPT partition table if you want to specify a boot partition using root=PARTUUID=partition-uuid. Does the root=PARTUUID option work for you? Can you point to some documentation on how you can use root=PARTUID=partition-uuid with an DOS/MBR partition table? I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. Anybody can write a program to gnerate and print a UUID for a partition. What matters is what the _kernel_ thinks the partition UUID is. I added some printk() calls to the kernel mount code to print out the parition UUIDs. They don't match the UUIDs printed by blkid: kernel blkid sector UUID UUID sda1 64 0004c99d-0166E1C3CF7C012A2E sda2 209715264 0004c99d-02e9a3eb9e-10d0-4075-aacf-018219cf77a3 sda3 211812416 null n/a sda4 n/a n/a n/a sda5 211812480 0004c99d-05ab4724ab-9030-4217-8582-00f0abe1a48e sda6 421527744 0004c99d-06n/a sda7 429916416 0004c99d-0713c0fbde-db8a-4784-861a-b3f4e4cdd8f5 sda8 639631680 0004c99d-08d0f87d87-002c-4d12-b5f3-193d9b0bebee sda9 849346944 0004c99d-0903c479f0-ecf8-4060-885b-b350368deee8 sda10 1059062208 0004c99d-0a60acb3d3-ce8e-48ce-b197-858bc51a74ea sda11 1268777472 0004c99d-0bn/a sda12 1478492736 0004c99d-0cn/a sda13 1688208000 0004c99d-0dn/a sda14 1897923264 0004c99d-0en/a IOW, it appears that the blkid program is either just making stuff up or its the filesystem UUID rather than the partition UUID. I suspect the latter, since I notice that blkid doesn't print a UUID for paritions that don't have filesystems. One might think that one could use root=PARTUUID=0004c99d-06 instead of root=/dev/sda5, but the kernel will reject any partition UUID strings shorter than 36 characters. -- Grant Edwards grant.b.edwardsYow! ... I see TOILET at SEATS ... gmail.com
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, 2 Jul 2013 16:57:26 + (UTC), Grant Edwards wrote: IOW, it appears that the blkid program is either just making stuff up or its the filesystem UUID rather than the partition UUID. I suspect the latter, since I notice that blkid doesn't print a UUID for paritions that don't have filesystems. UUIDs are for filesystems, PARTUUIDs ae for partitions - blkid prints both, but only if both are present, which requires a GPT partition table. -- Neil Bothwick A man needs a mistress - just to break the monogamy signature.asc Description: PGP signature
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Neil Bothwick n...@digimed.co.uk wrote: On Tue, 2 Jul 2013 16:57:26 + (UTC), Grant Edwards wrote: IOW, it appears that the blkid program is either just making stuff up or its the filesystem UUID rather than the partition UUID. I suspect the latter, since I notice that blkid doesn't print a UUID for paritions that don't have filesystems. UUIDs are for filesystems, PARTUUIDs ae for partitions - blkid prints both, but only if both are present, which requires a GPT partition table. I found some references to blkid at one time generating PARTUUID values for MBR partitions, but that feature got removed. -- Grant Edwards grant.b.edwardsYow! How's the wife? at Is she at home enjoying gmail.comcapitalism?
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, Jul 2, 2013 at 11:57 AM, Grant Edwards grant.b.edwa...@gmail.com wrote: All the references Google can find for me say that you have to use a GPT partition table if you want to specify a boot partition using root=PARTUUID=partition-uuid. Does the root=PARTUUID option work for you? Can you point to some documentation on how you can use root=PARTUID=partition-uuid with an DOS/MBR partition table? As Neil alluded to, you can use UUID with MBR (instead of PARTUUID and GPT). I have DOS/MBR partition table and my kernel commandline looks like: root=UUID=1d21fa55-0fa9-4d43-8d41-8b4193900efa ro log_buf_len=1M quiet rootfstype=ext4 raid=noautodetect (along with an initramfs)
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Paul Hartman paul.hartman+gen...@gmail.com wrote: On Tue, Jul 2, 2013 at 11:57 AM, Grant Edwards grant.b.edwa...@gmail.com wrote: 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. All the references Google can find for me say that you have to use a GPT partition table if you want to specify a boot partition using root=PARTUUID=partition-uuid. Does the root=PARTUUID option work for you? Can you point to some documentation on how you can use root=PARTUID=partition-uuid with an DOS/MBR partition table? As Neil alluded to, you can use UUID with MBR (instead of PARTUUID and GPT). I have DOS/MBR partition table and my kernel commandline looks like: root=UUID=1d21fa55-0fa9-4d43-8d41-8b4193900efa ro log_buf_len=1M quiet rootfstype=ext4 raid=noautodetect (along with an initramfs) Yes, we've already discussed that if you have an initrd (or initramfs), and an 'init' program that handles it, you can use filesystem labels and filesystem uuids. The option we were discussing in the posting to which you replied is that of using the root=PARTUUID method which is handled directly by the kernel. I said that requires switching from MBR to GPT, and was told You don't need to switch to GPT for that. The evidence for that last statement seemed to be the fact the 'blkid' command prints out filesystem UUIDs. I tried using root=PARTUUID= with an MBR and the UUID values printed by 'blkid': it didn't work. I even modified the kernel to show the kernel's partition UUIDs that were being compared against. I still maintain that you _do_ need to switch to GPT to use root=PARTUUID but would welcome any evidence or documentation that indicates otherwise. -- Grant Edwards grant.b.edwardsYow! The Korean War must at have been fun. gmail.com
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Randolph Maa?en r.maasse...@gmail.com wrote: 2013/7/2 Grant Edwards grant.b.edwa...@gmail.com On 2013-07-02, Randolph Maa?en r.maasse...@gmail.com wrote: 2013/7/2 Grant Edwards grant.b.edwa...@gmail.com It looks like my options are: [...] 5) For the drive with the root parition on it switch from a DOS parition table to a GPT partition table and use the root=PARTUUID=whatever kernel option. You don't need to switch to GPT for that. I have a DOS partitioned disk and blkid prints the LABEL and UUID for each partition. And you can pass those values to the kernel via the root= parameter? Yep. The G in GPT just means that the type of the partition is stored as GUID/UUID. The partition ID is a separate value. I think you're confusing the partition UUID and the filesystem UUID (which I believe is what's printed by blkid). GPT provides a partition UUID you can use to tell the kernel where root is. DOS/MBR does not. -- Grant Edwards grant.b.edwardsYow! I just had my entire at INTESTINAL TRACT coated gmail.comwith TEFLON!
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Neil Bothwick n...@digimed.co.uk wrote: On Tue, 2 Jul 2013 15:16:15 + (UTC), Grant Edwards wrote: The PARTUUID= parition specifier format is handled directly by kernel code, so I don't see why it should require an initrd (unless the UUID values for MBR partitions aren't actually something the kernel knows about and are something made up from whole cloth by the blkid program) MBRs don't have PARTUUIDs do they? Don't confuse them with filesystem UUIDs as used in fstab. No, blkid does not print a PARTUUID value with an MBR. In only prints UUID values, which as you noted, are _filesystem_ UUIDs. If you want to use a filesystem UUID to locate the root partition, you need an initramfs/initrd which contains an 'init' program that finds the filesystem with the specified UUID, mounts that filesystem, and then does a root_pivot. -- Grant Edwards grant.b.edwardsYow! Hello. Just walk at along and try NOT to think gmail.comabout your INTESTINES being almost FORTY YARDS LONG!!
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
2013/7/2 Grant Edwards grant.b.edwa...@gmail.com On 2013-07-02, Neil Bothwick n...@digimed.co.uk wrote: On Tue, 2 Jul 2013 15:16:15 + (UTC), Grant Edwards wrote: The PARTUUID= parition specifier format is handled directly by kernel code, so I don't see why it should require an initrd (unless the UUID values for MBR partitions aren't actually something the kernel knows about and are something made up from whole cloth by the blkid program) MBRs don't have PARTUUIDs do they? Don't confuse them with filesystem UUIDs as used in fstab. No, blkid does not print a PARTUUID value with an MBR. In only prints UUID values, which as you noted, are _filesystem_ UUIDs. If you want to use a filesystem UUID to locate the root partition, you need an initramfs/initrd which contains an 'init' program that finds the filesystem with the specified UUID, mounts that filesystem, and then does a root_pivot. -- Grant Edwards grant.b.edwardsYow! Hello. Just walk at along and try NOT to think gmail.comabout your INTESTINES being almost FORTY YARDS LONG!! SCREW ME! Still messing around with these IDs. Sorry for disturbance. -- Mit freundlichen Grüßen / Best regards Randolph Maaßen
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Neil Bothwick n...@digimed.co.uk wrote: On Tue, 2 Jul 2013 15:09:28 + (UTC), Grant Edwards wrote: I had this problem on my Intel motherboard, and found out you can disable booting from external drives. Boot to removable devices or similar in the BIOS. Failing that, changing the boot order so that the firewire/USB device is at the very end of the boot list may help your situation. [...] I'd go for the firewire-as-a-module approach and add the module to /etc/conf.d/modules to make sure it is loaded ASAP. Yes, it is a kludge, but it is the simplest solution from a practical POV. I changed the firewire storage driver from in-kernel to module, and that looks like it solves the problem. It appears to get demand-loaded immediately after root is mounted. Next time I do an install, I think I'll try GPT... -- Grant Edwards grant.b.edwardsYow! Now, let's SEND OUT at for QUICHE!! gmail.com
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, Jul 2, 2013 at 3:27 PM, Grant Edwards grant.b.edwa...@gmail.com wrote: Can you point to some documentation on how you can use root=PARTUID=partition-uuid with an DOS/MBR partition table? As Neil alluded to, you can use UUID with MBR (instead of PARTUUID and GPT). I have DOS/MBR partition table and my kernel commandline looks like: root=UUID=1d21fa55-0fa9-4d43-8d41-8b4193900efa ro log_buf_len=1M quiet rootfstype=ext4 raid=noautodetect (along with an initramfs) Yes, we've already discussed that if you have an initrd (or initramfs), and an 'init' program that handles it, you can use filesystem labels and filesystem uuids. The option we were discussing in the posting to which you replied is that of using the root=PARTUUID method which is handled directly by the kernel. Ah, sorry, I missed that detail. I thought I was helping to clear up confusion, when in fact I was the confused one! :)
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Tue, 2 Jul 2013 20:40:20 + (UTC), Grant Edwards wrote: Next time I do an install, I think I'll try GPT... I can't think why any sane person would do otherwise. Who in their right mind would want to use a 30+year old format where any more than four partitions is a fragile kludge? :-O -- Neil Bothwick Eat shit - 50 million flies can't be wrong Use Microsoft . . . . . signature.asc Description: PGP signature
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-01, Alan McKinnon alan.mckin...@gmail.com wrote: On 01/07/2013 23:52, Grant Edwards wrote: I've just recently run into a problem where sometimes when a machine boots, the kernel can't find init. This appears to be because my grub configuration line says root=/dev/sda5 and _sometimes_ the drive that contains my root partition is sdb instead of sda. AFAICT, for the past 30 years the linux kernel was 100% consistent in the order that hard drives were labelled -- but recently that has seems to have changed. I use partition labels in my fstab, so that's not a problem, but after all these years, the kernel still doesn't know how to grok parition labels. Are we really expected now to set up an initrd just so that the kernel can find the root partition?? Where have you been for the past 6 months? Did you miss the entire clusterfuck debate about latest udev tricks? No. Those names depend only on the order in which devices are discovered, and that process has always been indeterminate. Really? I've been running Linux on a lot of machines for 30 years -- often on machines with a half-dozen hard drives -- and I never saw drive order change from one reboot to the next until today. That's quite a lucky streak. udev used to get in the middle and rename things in an arbitrary but defined order, it no longer does this. How did udev get in the middle? It somehow ran before the kernel mounted root and started 'init'? We discussed this whole subject *to death* over the last many months I remember that discussion, but I don't see how it's relelvent to events that occur before init starts. -- Grant
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-01, Paul Hartman paul.hartman+gen...@gmail.com wrote: On Mon, Jul 1, 2013 at 4:52 PM, Grant Edwards grant.b.edwa...@gmail.com wrote: I've just recently run into a problem where sometimes when a machine boots, the kernel can't find init. This appears to be because my grub configuration line says root=/dev/sda5 and _sometimes_ the drive that contains my root partition is sdb instead of sda. AFAICT, for the past 30 years the linux kernel was 100% consistent in the order that hard drives were labelled -- but recently that has seems to have changed. I wonder if it could be related to parallel initialization of disks. Apparently so. I think there's a kernel toggle for that. I'll look into it. Are we really expected now to set up an initrd just so that the kernel can find the root partition?? As far as I know, the answer is yes. FWIW, I always resisted making an initrd until very recently, but wanted to use UUID in my bootup on my new system. I used this command (which I re-run whenever I deploy a new kernel): dracut -H -o i18n -o resume -o usrmount --force /boot/initramfs.img And then added one line to my grub2 config: initrd /initramfs.img and it just simply works... though it's still a bit of black magic to me, It's not really that complex. There are two ways to get the kernel to use an initial ram fs as root: the bootloader loads the initial ram image into ram or it gets linked into the kernel when the kernel is built. and every time I reboot I feel a bit of nervousness when I see Loading initial ramdisk... and don't breathe until it succeeds. :) I've got nothing against initramfs -- on my embedded systems root starts out as an initramfs and stays that way. I just don't see why I should be forced to have one. -- Grant
Re: [gentoo-user] Re: Can't find init due to inconsistent drive order
On Jul 1, 2013 9:45 PM, Grant Edwards grant.b.edwa...@gmail.com wrote: On 2013-07-01, Alan McKinnon alan.mckin...@gmail.com wrote: On 01/07/2013 23:52, Grant Edwards wrote: I've just recently run into a problem where sometimes when a machine boots, the kernel can't find init. This appears to be because my grub configuration line says root=/dev/sda5 and _sometimes_ the drive that contains my root partition is sdb instead of sda. AFAICT, for the past 30 years the linux kernel was 100% consistent in the order that hard drives were labelled -- but recently that has seems to have changed. I use partition labels in my fstab, so that's not a problem, but after all these years, the kernel still doesn't know how to grok parition labels. Are we really expected now to set up an initrd just so that the kernel can find the root partition?? Where have you been for the past 6 months? Did you miss the entire clusterfuck debate about latest udev tricks? No. Those names depend only on the order in which devices are discovered, and that process has always been indeterminate. Really? I've been running Linux on a lot of machines for 30 years -- often on machines with a half-dozen hard drives -- and I never saw drive order change from one reboot to the next until today. That's quite a lucky streak. Since Linus started writing Linux in 1991 (22 years ago), I want to know which time machine did you use. Regards. -- Canek Peláez Valdés
[gentoo-user] Re: Can't find init due to inconsistent drive order
On 2013-07-02, Canek Pel??ez Vald??s can...@gmail.com wrote: On Jul 1, 2013 9:45 PM, Grant Edwards grant.b.edwa...@gmail.com wrote: Those names depend only on the order in which devices are discovered, and that process has always been indeterminate. Really? I've been running Linux on a lot of machines for 30 years -- often on machines with a half-dozen hard drives -- and I never saw drive order change from one reboot to the next until today. That's quite a lucky streak. Since Linus started writing Linux in 1991 (22 years ago), I want to know which time machine did you use. Doh! I meant 20 years. The first time was just a typo, and then somehow after reading my original post I did it again. I started running Linux in 93 with a friend's Yggdrasil CD and a Sun CD drive I borrowed from work. I think that was on a 25MHz 486 with 4MB of RAM and two 30MB hard drives. -- Grant
