boot from backup copy of fc5 on usb external disk?
main fc5 system on sda1 [by...@bootp drhmail09]$uname -a Linux bootp 2.6.17-1.2174_FC5 #1 Tue Aug 8 15:30:55 EDT 2006 i686 i686 i386 GNU/Linux I am trying to boot from a backupcopy of my mainfc5 which backupcopy is in top dir of the usb disk /dev/sdc1 mounted as /media/disk-1 when in mainfc5 that usbdisk is one large reiserfs partition sdc1 1) first problem if i use in grub.conf in a new stanza root (hd2,0) corresponding to /dev/sdc1 then boot fails immediately "hd2 does not exist" I also note that when booting my mainfc5 there is an early message (not seen in dmesg) something like cant find special .../dev/sdc1 then later in the boot process it does find sdc1: [by...@bootp drhmail09]$ dmesg |grep sdc1 sdc: sdc1 ReiserFS: sdc1: found reiserfs format "3.6" with standard journal ReiserFS: sdc1: using ordered data mode ReiserFS: sdc1: journal params: device sdc1, size 8192, journal first block 18, max trans len 1024, max batch 900, max commit age 30, max trans age 30 ReiserFS: sdc1: checking transaction log (sdc1) ReiserFS: sdc1: Using r5 hash to sort names both pieces of evidence imply that usb disk not available early enough in the boot process Is there any fix for this or a workaround? 2) second problem if i cheat and copy the /boot dir from the usb fc5copy into /dev/sdb3 and use root (hd1,2) in grub.conf then again attempting to boot from usb gets to ok booting the kernel but shortly fails with "could not find /dev/root" and other "couldnotfind" then kernel panic,locks up googling "could not find /dev/root" reveals that this has been a problem in several fedora last few yrs, (most or all of them _not_ using external usb disk) fc6,fc7 maybe i saw one on fc8 as well but no clean solution, in general not obvious (to me) why it occurred. some cases helped with use LABELs, some not. ( i tried this, no help) some cases helped with complex(to me) mkinitrd some cases helped with earlier kernel, but i dont see explanation of why In my case, the following stanza using an older kernel does boot! but has other problems. eg networking not avail until i do a 2nd boot I got the older kernel from some oddball kubuntu thing i was experimenting with way back title FC5copy (2.6.15-26-386) usbfc5 /media/disk-1 (hd1,2)sdb3 rootusb root (hd1,2) ## sdb3 kernel /boot/vmlinuz-2.6.15-26-386 ro root=LABEL=rootusb rhgb quiet initrd /boot/initrd.img-2.6.15-26-386 this kernel 2.6.15-26-386 instead of what i use in mainfc5 2.6.17-1.2174_FC5 Is there any current advice re "could not find /dev/root"? has anyone seen it in f8,f9,f10? thanks for any advice yes i know i should get f9 or f10. but i would like to see if I can find clean method to booting from usbexternal disk. Jack -- fedora-list mailing list fedora-list@redhat.com To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
Re: boot from backup copy of fc5 on usb external disk?
jackson byers wrote: > main fc5 system on sda1 > [by...@bootp drhmail09]$uname -a > Linux bootp 2.6.17-1.2174_FC5 #1 Tue Aug 8 15:30:55 EDT 2006 i686 i686 > i386 GNU/Linux > > I am trying to boot from a backupcopy of my mainfc5 > which backupcopy is in top dir of the usb disk /dev/sdc1 > mounted as /media/disk-1 when in mainfc5 > that usbdisk is one large reiserfs partition sdc1 > > 1) first problem > if i use in grub.conf in a new stanza > root (hd2,0) corresponding to /dev/sdc1 > then boot fails immediately "hd2 does not exist" > Grub uses the BIOS to access the drives. It looks like your BIOS is not mapping the USB drive. This is BIOS dependent. > > > 2) second problem > if i cheat and copy the /boot dir from the usb fc5copy into /dev/sdb3 > and use root (hd1,2) in grub.conf > then again attempting to boot from usb gets to ok booting the kernel > > but shortly fails with "could not find /dev/root" and other "couldnotfind" > Did you include the usb_storage module in your initrd? If not, you do not have the proper drivers to access the root file system on your USB drive. How you manage things is up to you. I kind of like to set up a distribution on a USB drive so that it will boot off of any machine that will boot off of a USB drive. This means that you nave to select the USB drive as the boot device using the BIOS. (I hit F12, and pick the boot device on my machine.) As far as Grub is conserved, it is booting off of drive 0. You still need usb_storage and the USB controller drivers in the initrd. Mikkel -- Do not meddle in the affairs of dragons, for thou art crunchy and taste good with Ketchup! signature.asc Description: OpenPGP digital signature -- fedora-list mailing list fedora-list@redhat.com To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
RE: boot from backup copy of fc5 on usb external disk? [solved]
feb 17 2009 success booting fc5copy on usb external disk thanks to Mikkel for pointing me in right direction this fc5copy was not an install, but rather a backup copy of my mainfc5 on a scsi disk on sda1 for days i was getting "cant find /dev/root kernel panic" finally fixed that with proper mkinitrd see below then was getting cant access resume device /dev/sda2 for days now understand that occuring bc of disk reordering part of my problem was using reisrfs on the usb, but ext3 on mainfc5 on sda1 this required an extra --preload=reiserfs in mkinitrd cmd and a further editing of the mkrootdev line in the initrd init file. r...@bootp ~]# mkdir cleanrs2; cd cleanrs2 [r...@bootp cleanrs2]# mkinitrd --preload=ehci-hcd --preload=usb-storage --preload=reiserfs /boot/initrd_usbrs2.img 2.6.17-1.2174_FC5 expand: [r...@bootp cleanrs2]# gunzip -c initrd_usbrs2.img |cpio -i 5551 blocks [r...@bootp cleanrs2]# ls bin dev etc init initrd_usbrs2.img lib proc sbin sys sysroot now modify the mkrootdev line from mkrootdev -t ext3 -o defaults,ro /dev/sda1 to mkrootdev -t reiserfs -o defaults,ro /dev/sdc1 repack: [r...@bootp cleanrs2]# find . |cpio -c -o |gzip -9 >../initrd_usbrs2.img at this point, still getting "cant access resume device /dev/sda2" but no longer getting caught in "cant find /dev/root" next problem was getting caught in filesytem check on sda1,sda3 which eventually forced a reboot, but no kernel panic! The sda1,sda3 problems evidently bc of reordering of the disks (see below) I got around this gotcha by commenting out the sda1, sda3 lines in the usb fstab my mainfc5 grub.conf has following stanza for the usb boot title FC5copy (2.6.17-1.2174_FC5_usbrs2.img) /media/disk-1 (hd1,2) root (hd1,2) ## sdb3 kernel /boot/vmlinuz-2.6.17-1.2174_FC5 ro root=LABEL=rootusb rhgb quiet initrd /boot/initrd_usbrs2.img when booted up from usb: fdisk clearly shows disks have been reordered [r...@bootp ~]# fdisk -l Disk /dev/sda: 250.0 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 1 30401 244196001 83 Linux <<< root (hd1,2) in grub.conf this is just a holding tank for the /boot files: I am not treating it as a "separate /boot partition", not listed in fstab regards, Jack -- fedora-list mailing list fedora-list@redhat.com To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
