Difference between revisions of "Installing Arch Linux on a USB key"

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[[Category:Getting and installing Arch]]
 
[[Category:Getting and installing Arch]]
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[[es:Installing Arch Linux on a USB key]]
 
[[it:Installing Arch Linux on a USB key]]
 
[[it:Installing Arch Linux on a USB key]]
 
[[zh-CN:Installing Arch Linux on a USB key]]
 
[[zh-CN:Installing Arch Linux on a USB key]]
{{Out of date}}
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{{Article summary start}}
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{{Article summary text|Guide to installing, configuring and using a full-featured Arch Linux system on a USB flash drive.}}
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{{Article summary heading|Related}}
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{{Article summary wiki|Beginners' Guide}}
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{{Article summary wiki|Installation Guide}}
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{{Article summary wiki|General Recommendations}}
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{{Article summary wiki|General Troubleshooting}}
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{{Article summary end}}
  
This page discusses how to perform a regular Arch installation onto a USB key (or "flash drive"). The result will be a system that will be updated through normal use. Consider whether you're instead interested in [[USB Installation Media]].
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This page explains how to perform a regular Arch installation onto a USB key (or "flash drive"). In contrast to having a LiveUSB as covered in [[USB Installation Media]], the result will be a persistent installation identical to normal installation to HDD, but on a USB flash drive.
  
== Grab a big enough USB key ==
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== Preparation ==
If installing KDE and a large amount of applications, 3 GiB is the recommended minimum. GNOME and Xfce4, along with a typical set of packages for a desktop (GIMP, Pidgin, OpenOffice, Firefox, flashplugin) can be installed on a 2 GiB stick, leaving a small amount of room for user data.
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{{Note|At least 2 GiB of storage space is recommended. A modest set of packages will fit, leaving a little free space for storage.}}
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There are various ways of installing Arch on a USB stick, the simplest being from within Arch itself:
  
== Install from... ==
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* If you are already running Arch, simply install {{Pkg|arch-install-scripts}} and proceed with the [https://wiki.archlinux.org/index.php/Installation_Guide Installation Guide] just like you would from the iso, but you will not be using /dev/sda. Use {{ic|lsblk}} to get the /dev/sd* name of your USB key prior to installation.
* An Arch Linux CD can be used to install Arch onto the USB key, via booting the CD and following the [https://wiki.archlinux.org/index.php/Installation_Guide Installation Guide].
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{{Warning|If you mistakingly format /dev/sda, you are likely to go about deleting everyting on your hard drive.}}
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* An Arch Linux CD/USB can be used to install Arch onto the USB key, via booting the CD/USB and following the [https://wiki.archlinux.org/index.php/Installation_Guide Installation Guide]. If booting from a Live USB, the installation will have to be made on a different USB stick.
 
* Or, if you have another linux computer available (it need not be Arch), you can follow the instructions to [[Install_from_Existing_Linux|install from existing linux]], and then skip to the configuration section.
 
* Or, if you have another linux computer available (it need not be Arch), you can follow the instructions to [[Install_from_Existing_Linux|install from existing linux]], and then skip to the configuration section.
* In case you are already running Arch, simply install {{Pkg|arch-install-scripts}} and then install just like you would from the iso, but you will not be using /dev/sda, most likely it will be /dev/sdb. (Be very careful. You don't want to go about deleting everyting on your hard drive)
 
  
 
== Installation ==
 
== Installation ==
 
 
Follow the [https://wiki.archlinux.org/index.php/Installation_Guide Installation Guide] as you normally would, with these exceptions:
 
Follow the [https://wiki.archlinux.org/index.php/Installation_Guide Installation Guide] as you normally would, with these exceptions:
  
 
* If cfdisk fails with "Partition ends in the final partial cylinder" fatal error, the only way to proceed is to kill all partitions on the drive. Open another terminal ({{keypress|Alt+F2}}), type {{ic|fdisk /dev/sdX}} (where {{ic|sdX}} is your usb drive), print partition table (p), check that it's ok, delete it (d) and write changes (w). Now return to cfdisk.
 
* If cfdisk fails with "Partition ends in the final partial cylinder" fatal error, the only way to proceed is to kill all partitions on the drive. Open another terminal ({{keypress|Alt+F2}}), type {{ic|fdisk /dev/sdX}} (where {{ic|sdX}} is your usb drive), print partition table (p), check that it's ok, delete it (d) and write changes (w). Now return to cfdisk.
* It is highly recommended to review the [http://wiki.archlinux.org/index.php/SSD#Tips_for_Minimizing_SSD_Read.2FWrites Tips for Minimizing SSD Read/Writes] on the [[SSD]] wiki article prior to selecting a filesystem.  To sum up, ext4 with a journal should be fine.  Recognize that flash has a limited number of writes, and a journaling file system will take some of these as the journal is updated.  For this same reason, it is best to forgo a swap partition. Note that this does not affect installing onto a USB hard drive.
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* It is highly recommended to review the [https://wiki.archlinux.org/index.php/SSD#Tips_for_Minimizing_SSD_Read.2FWrites Tips for Minimizing SSD Read/Writes] on the [[SSD]] wiki article prior to selecting a filesystem.  To sum up, ext4 without a journal should be fine.  Recognize that flash has a limited number of writes, and a journaling file system will take some of these as the journal is updated.  For this same reason, it is best to forgo a swap partition. Note that this does not affect installing onto a USB hard drive.
* When editing the {{ic|/etc/mkinitcpio.conf}}, add the {{ic|usb}} hook to the hooks array right after udev. This is necessary for appropriate module loading in early userspace.
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* Before creating the initial RAM disk {{ic|# mkinitcpio -p linux}}, in {{ic|/etc/mkinitcpio.conf}} add the {{ic|block}} hook to the hooks array right after udev. This is necessary for appropriate module loading in early userspace.
  
 
== Configuration ==
 
== Configuration ==
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{{Note|When grub is installed on the USB key, the key will always be hd0,0}}
 
{{Note|When grub is installed on the USB key, the key will always be hd0,0}}
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{{Note|It seems that current versions of GRUB2 will automatically default to using uuid.  The following directions are for GRUB legacy}}
  
 
With the static /dev/sdaX:
 
With the static /dev/sdaX:

Revision as of 03:39, 9 January 2013

Summary help replacing me
Guide to installing, configuring and using a full-featured Arch Linux system on a USB flash drive.
Related
Beginners' Guide
Installation Guide
General Recommendations
General Troubleshooting

This page explains how to perform a regular Arch installation onto a USB key (or "flash drive"). In contrast to having a LiveUSB as covered in USB Installation Media, the result will be a persistent installation identical to normal installation to HDD, but on a USB flash drive.

Preparation

Note: At least 2 GiB of storage space is recommended. A modest set of packages will fit, leaving a little free space for storage.

There are various ways of installing Arch on a USB stick, the simplest being from within Arch itself:

  • If you are already running Arch, simply install arch-install-scripts and proceed with the Installation Guide just like you would from the iso, but you will not be using /dev/sda. Use lsblk to get the /dev/sd* name of your USB key prior to installation.
Warning: If you mistakingly format /dev/sda, you are likely to go about deleting everyting on your hard drive.
  • An Arch Linux CD/USB can be used to install Arch onto the USB key, via booting the CD/USB and following the Installation Guide. If booting from a Live USB, the installation will have to be made on a different USB stick.
  • Or, if you have another linux computer available (it need not be Arch), you can follow the instructions to install from existing linux, and then skip to the configuration section.

Installation

Follow the Installation Guide as you normally would, with these exceptions:

  • If cfdisk fails with "Partition ends in the final partial cylinder" fatal error, the only way to proceed is to kill all partitions on the drive. Open another terminal (Template:Keypress), type fdisk /dev/sdX (where sdX is your usb drive), print partition table (p), check that it's ok, delete it (d) and write changes (w). Now return to cfdisk.
  • It is highly recommended to review the Tips for Minimizing SSD Read/Writes on the SSD wiki article prior to selecting a filesystem. To sum up, ext4 without a journal should be fine. Recognize that flash has a limited number of writes, and a journaling file system will take some of these as the journal is updated. For this same reason, it is best to forgo a swap partition. Note that this does not affect installing onto a USB hard drive.
  • Before creating the initial RAM disk # mkinitcpio -p linux, in /etc/mkinitcpio.conf add the block hook to the hooks array right after udev. This is necessary for appropriate module loading in early userspace.

Configuration

  • Make sure that /etc/fstab includes the correct partition information for /, and for any other partitions on the USB key. If the usb key is to be booted on several machines, it is quite likely that devices and number of available hard disks vary. So it is advised to use UUID or label:

To get the proper UUIDs for your partitions issue blkid

  • menu.lst, the Grub configuration file, should be edited to (loosely) match the following:
Note: When grub is installed on the USB key, the key will always be hd0,0
Note: It seems that current versions of GRUB2 will automatically default to using uuid. The following directions are for GRUB legacy

With the static /dev/sdaX:

root (hd0,0)
kernel /boot/vmlinuz-linux root=/dev/sda1 ro
initrd /boot/initramfs-linux.img

When using label your menu.lst should look like this:

root (hd0,0)
kernel /boot/vmlinuz-linux root=/dev/disk/by-label/Arch ro
initrd /boot/initramfs-linux.img

And for UUID, it should be like this:

root (hd0,0)
kernel /boot/vmlinuz-linux root=/dev/disk/by-uuid/3a9f8929-627b-4667-9db4-388c4eaaf9fa ro
initrd /boot/initramfs-linux.img

Tips

Painless boot on different machines without using UUID

When using the USB key on various target machines, it is helpful to have multiple entries in GRUB, for machines with different setups. For example, the GRUB configuration could contain:

# (0) Arch Linux
title  Arch Linux (first drive)
root   (hd0,0)
kernel /boot/vmlinuz-linux root=/dev/sda1 ro
initrd /boot/initramfs-linux.img

As well as

# (1) Arch Linux
title  Arch Linux (second drive)
root   (hd0,0)
kernel /boot/vmlinuz-linux root=/dev/sdb1 ro
initrd /boot/initramfs-linux.img

And so forth, giving you the option to select a configuration for a wider variety of machines. However, changing the root= option in GRUB does not change /etc/fstab and you must do something (in our example using udev symlink), so the root partition will always be mounted correctly.

  • Run udevinfo -p /sys/block/sdx/ -a (where sdx is the device name of your usb key)
  • Find unique information pertaining to your usb key. I chose SYSFS{model}=="DataTraveler 2.0"
  • Make a new file: /etc/udev/udev.rules/10-my-usb-key.rules and insert:
KERNEL=="sd**", SYSFS{product}=="DataTraveler 2.0", SYMLINK+="WHATEVERYOUWANTOTCALLIT%n"
(KERNEL=="sd**" is because the kernel - 2.6.16 here - names all usb devices sd as it uses the scsi sub-system and you want to look at every sd device and apply the setting to every partition), with SYSFS{model}== being the unique identifier collected from udevinfo.
  • Run /etc/start-udev uevents and make sure the symlinks appears in /dev.
  • If so, edit /etc/fstab, replacing your old sdx with the new symlinks.

Optimizing for the lifespan of flash memory

See Also