imported>ThorstenStaerk |
imported>ThorstenStaerk |
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| − | Modern computers can boot from [[USB]] storage like disks and sticks. This article shows how to [[install]] Linux on a USB disk so that you can boot from it. It lists the following approaches: | + | Modern computers can boot from [[USB]] storage like disks and sticks. But how to [[install Linux]] there to have a USB disc or stick bootable? Here are some approaches: |
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| | {| class="wikitable sortable" border=1 | | {| class="wikitable sortable" border=1 |
| − | ! approach !! time to succeed !! remarks | + | ! approach !! OS of your computer must be !! distro of bootdisk will be !! time to succeed |
| | |- | | |- |
| − | | Unetbootin || ? || works with all distributions supported by unetbootin | + | | [[install Linux on a USB disk with Unetbootin]] || Linux or Windows || any || 1 hour, depends on your choices |
| | |- | | |- |
| − | | Knoppix || 10 min || only works with Knoppix | + | | [[install Linux on a USB disk with Knoppix]] || any || Knoppix || 30 min, depends on disk speed and size |
| | |- | | |- |
| − | | SUSE Studio || 1 hour || only works with SUSE distros | + | | [[install Linux on a USB disk with SUSE Studio]] || Linux or Windows || SUSE || 1 hour |
| | |- | | |- |
| − | | Cloning-approach || 2 hours || work with almost all distributions | + | | [[install Linux on a USB disk by cloning your computer]] || any Linux || any || 2 hours |
| | |} | | |} |
| | | | |
| − | | + | = See also = |
| − | = the unetbootin approach =
| + | * [[install SUSE Linux on netbooks]] |
| − | Download unetbootin from http://unetbootin.sourceforge.net. Start it and select which distribution you want to have installed on what disk.
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| − | | |
| − | = the knoppix approach =
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| − | Boot your system from [[knoppix]], then [[open a console]] and enter
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| − | flash-knoppix
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| − | Then select a harddisk or a USB Flash drive. This will be made boot Knoppix.
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| − | | |
| − | == additional information ==
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| − | Make sure you have a graphical display. This installer will give a lot more messages than the text-based installer.
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| − | | |
| − | == TroubleShooting ==
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| − | * Your USB Flash drive must be vfat-formatted. Otherwise, flash-knoppix will not work.
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| − | | |
| − | = the SUSE Studio approach =
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| − | Go to www.susestudio.com. Choose your favorite SUSE, add packages as you like. Tell the web site to build a USB stick from it. Download the image and put it onto your USB stick.
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| − | | |
| − | For example, if your USB stick is /dev/sdh, use something like
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| − | dd if=usbstick.i686-0.0.1.raw of=/dev/sdh
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| − | | |
| − | = the cloning approach =
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| − | The cloning approach is the manual approach where you clone your harddisk to a USB harddisk and then write a bootsector using [[grub]].
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| − | | |
| − | == Boot your favorite Linux ==
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| − | This has been tested with SUSE Linux 10.0 and Ubuntu 7.04.
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| − | | |
| − | == Connect the USB disk ==
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| − | Attach the USB disk and type <tt>[[dmesg]]</tt>. At the end of the messages, you will find something like "Attached SCSI device to /dev/sda". Then you know your USB disk's device name is /dev/sda. In this tutorial, we assume the device name is /dev/sda.
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| − | | |
| − | == Partition the USB disk ==
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| − | [[fdisk]] /dev/sda
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| − | In this tutorial, we will assume you create a partition /dev/sda1 for your root ( / ) directory.
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| − | | |
| − | == Format the USB disk ==
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| − | mkfs -t ext3 /dev/sda1
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| − | | |
| − | == Clone your system ==
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| − | Copy over all files from / to your USB disk. See also [[Cloning]].
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| − | [[mkdir]] -p /mnt/sda1
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| − | [[mount]] /dev/sda1 /mnt/sda1
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| − | [[cd]] /
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| − | [[tar]] -c [[Bash_operators#.24.28.29|$(]][[ls]] -1 [[piping||]] [[grep]] -Ev "[[regex|proc|sys|tmp|media|mnt]]"[[Bash_operators#.24.28.29|)]] [[piping||]] (cd /mnt/sda1; tar -xv)
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| − | | |
| − | '''You should know''' that you will need the /dev folder to create the ramdisk later. You can also use tar -cl ('''l'''ocal filesystems only), but that might exclude your /boot partition.
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| − | | |
| − | == Make your USB disk bootable ==
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| − | Here are two possibilities for making the disk bootable, it is not unusual that one fails. Try the uppermost first. We assume your USB disk is drive ''/dev/sdx'' mounted to ''/mnt/sdx''.
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| − | | |
| − | === Possibility (1) ===
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| − | $ [[cp -pr]] ''/dev/sdx*'' ''/mnt/sdx1''/dev
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| − | $ [[cd]] ''/mnt/sdx1''
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| − | $ [[chroot]] .
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| − | Now make sure you can access all devices from /boot/grub/device.map.
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| − | $ mount /proc
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| − | $ grub-install ''/dev/sdx''
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| − | $ exit
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| − | | |
| − | === Possibility (2) ===
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| − | $ grub-install --recheck --root-directory=''/mnt/sdx1'' ''/dev/sdx''
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| − | Probing devices to guess BIOS drives. This may take a long time.
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| − | Installation finished. No error reported.
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| − | This is the contents of the device map /mnt/sda1/boot/grub/device.map.
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| − | Check if this is correct or not. If any of the lines is incorrect,
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| − | fix it and re-run the script `grub-install'.
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| − |
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| − | (fd0) /dev/fd0
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| − | (hd0) /dev/hda
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| − | (hd1) /dev/hdb
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| − | (hd2) ''/dev/sdx''
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| − | | |
| − | === TroubleShooting ===
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| − | ==== The file /boot/grub/stage1 not read correctly ====
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| − | * '''Symptome''' is that grub-install fails with the message
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| − | The file /boot/grub/stage1 not read correctly
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| − | | |
| − | * '''Reason''' can be that your partition type is incorrect, e.g. like this:
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| − | $ fdisk -l
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| − |
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| − | Disk ''/dev/sdx'': 160.0 GB, 160041885696 bytes
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| − | 255 heads, 63 sectors/track, 19457 cylinders
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| − | Units = cylinders of 16065 * 512 = 8225280 bytes
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| − |
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| − | Device Boot Start End Blocks Id System
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| − | ''/dev/sdx1'' * 1 19456 156280288+ '''c W95 FAT32 (LBA)'''
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| − |
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| − | * '''Solution''' can be to correct your partition type to 83 (Linux) using [[fdisk]].
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| − | | |
| − | == Edit your initial ramdisk ==
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| − | The initial ramdisk ([[initrd]]) must contain the modules needed to load usb storage. We will use [[mkinitrd]] to rebuild your initial ramdisk. First, change to your system on the USB disk:
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| − | cd ''/mnt/sdx1''
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| − | chroot .
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| − | mount /proc
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| − | Now have a look at the drivers that are loaded by the initial ramdisk.
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| − | | |
| − | === SUSE ===
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| − | For [[SUSE]], your drivers file is /etc/sysconfig/kernel.
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| − | You will find a line starting with INITRD_MODULES= in /etc/sysconfig/kernel. It should look like this:
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| − | INITRD_MODULES="jbd reiserfs ext3 usbcore usb_storage scsi_mod sd_mod uhci_hcd ehci-hcd sbp2 sr_mod"
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| − | it can also contain more modules. Verify this line exists, then, create the initial ramdisk:
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| − | mkinitrd
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| − | | |
| − | === Ubuntu ===
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| − | For [[Ubuntu]], your drivers file is /etc/modules. It should look at least like this (it can also contain more modules):
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| − | <pre>
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| − | # /etc/modules: kernel modules to load at boot time.
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| − | #
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| − | # This file contains the names of kernel modules that should be loaded
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| − | # at boot time, one per line. Lines beginning with "#" are ignored.
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| − | | |
| − | fuse
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| − | lp
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| − | usb_storage
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| − | uhci_hcd
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| − | usbcore
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| − | usbhid
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| − | sr_mod
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| − | sd_mod
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| − | scsi_mod
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| − | </pre>
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| − | After you verified the file exists, create your [[initrd]] with the command:
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| − | mkinitramfs -o /boot/initrd.img
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| − | | |
| − | == Use a unique device name ==
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| − | If you now boot from your USB disk, it might be that it appears under another name than /dev/sda. To circumvent this problem, we will now use the disk's unique ID instead of /dev/sda. Try
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| − | [[hwinfo]] --[[partition]]
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| − | You will get a line similar to the following:
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| − | Device Files: ''/dev/sda1'', /dev/disk/by-id/usb-CompanyXXXXXX,_Inc._USB_Mass_Stor
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| − | age_Device_100-part1, /dev/disk/by-path/pci-0000:00:1d.7-usb-0:3:1.0-scsi-0:0:0:
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| − | 0-part1, ''/dev/disk/by-uuid/84ff6790-9b69-4401-9ba2-43d044af1d30'', /dev/disk/by-la
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| − | bel/Whatever
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| − | Now you know your partition is not only accessible via ''/dev/sda1'', but also via ''/dev/disk/by-uuid/84ff6790-9b69-4401-9ba2-43d044af1d30''.
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| − | | |
| − | === /etc/fstab ===
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| − | You can now edit the [[fstab]] on your USB disk:
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| − | [http://userbase.kde.org/KWrite kwrite] /mnt/sda1/etc/fstab
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| − | there is one line for the mountpoint '''/''', maybe:
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| − | ''/dev/sda1'' / ext2 defaults 1 1
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| − | In our example, you would change this line to
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| − | ''/dev/disk/by-uuid/84ff6790-9b69-4401-9ba2-43d044af1d30'' / ext2 defaults 1 1
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| − | | |
| − | === /boot/grub/menu.lst ===
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| − | In /mnt/sda1/boot/grub/menu.lst, you will find some lines telling the kernel where to find the root (/) file system, maybe:
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| − | kernel /boot/vmlinuz-2.6.20-16-generic root=''/dev/sda1'' ro quiet splash
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| − | not to boot from the wrong partition, you can also replace them:
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| − | kernel /boot/vmlinuz-2.6.20-16-generic root=UUID=''84ff6790-9b69-4401-9ba2-43d044af1d30'' ro quiet splash
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| − | | |
| − | == Try booting from your disk ==
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| − | If there are problems, continue with TroubleShooting.
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| − | | |
| − | == TroubleShooting ==
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| − | === GRUB - nothing else ===
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| − | * When booting from USB, I get a line saying
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| − | GRUB
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| − | nothing else.
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| − | : This can be a problem with your device map. Keep in mind that, when booting from USB, your USB disk corresponds to (hd0), the first harddisk. grub-install will tell you where its device map is - try correcting it.
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| − | | |
| − | === Error 17 after boot menu ===
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| − | * After choosing an item from the [[grub]] menu, I get a line saying
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| − | Error 17: Cannot mount selected partition
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| − | : most probably, your device order has changed. For example, if you [[installed linux]] from CD and your IDE harddisk was device 0, it may now be device 1 after [[Booting from USB]]. In this case change
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| − | root (hd''1'',1)
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| − | to
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| − | root (hd''0'',1)
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| − | Please note that ''1'' is simply an example for a partition, it may also be any other number.
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| − | | |
| − | === Error 17 before boot menu ===
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| − | * Instead of getting the [[grub]] menu, I get a line saying nothing else but
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| − | Error 17
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| − | : most probably, your device order has changed and grub searches its menu (stage) on the wrong disk. You will have to do grub-install again.
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| − | | |
| − | === Error 21 before boot menu ===
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| − | * instead of getting the [[grub]] menu, I get a line saying
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| − | Error 21
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| − | : Solution was to correct ''/mnt/sda3''/boot/grub/device.map and ''/mnt/sda3''/boot/grub/menu.lst, the re-do a grub-install.
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| − | | |
| − | === Waiting for /dev/sda to appear ===
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| − | * After selecting the boot entry in the [[grub]] menu, you get some lines of messages then the boot process stops with the message
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| − | Waiting for ''/dev/sda'' to appear
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| − | : your USB disk is recognized and supported by your [[BIOS]], but your initrd's drivers do not recognize it. You will have to edit your initial ramdisk to contain the correct drivers, as discussed under initrd.
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| − | | |
| − | === No bootable partition in table ===
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| − | * After starting the computer, you get a line saying
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| − | No bootable partition in table
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| − | : you do not have a partition that is marked as bootable. Use [[fdisk]]'s "a" command to set the bootable flag of ''/dev/sda1''.
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| − | | |
| − | == What comes next ==
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| − | Now that you can boot from your USB disk, you should be aware that you cannot write very often to a specific sector, so you should make /tmp a [[ramdisk]] like this:
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| − | mount -t tmpfs tmpfs /tmp -o size=512M
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| − | | |
| − | | |
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