Skip to content

Latest commit

 

History

History
297 lines (208 loc) · 9.43 KB

boot-from-microsd-instead-of-external-drive.md

File metadata and controls

297 lines (208 loc) · 9.43 KB
layout
title description tableOfContents outline pagination
visible
true
visible
visible
true
visible
true
visible
true

Boot from microSD instead of an external drive

If the Raspberry Pi cannot boot from your external drive, you can boot from a microSD card and store all the application data on the external drive.

{% hint style="warning" %} Difficulty: Medium {% endhint %}

There are a few additional steps compared to the default RaMiX guide to boot from a microSD card and store the data on an external drive.

When writing Raspberry Pi OS to the boot medium, use a high endurance microSD card of 16+ GB instead of the external drive.

System configuration

  1. Connect your external drive to the Raspberry Pi using one of the blue USB 3.0 ports.
  2. Follow the Configuration section until you reach the Data directory section, which we will skip and continue with the steps below.

{% hint style="info" %} Remember: if your external drive performs poorly during the Check Drive Performance step, refer to the Fix Bad USB3 performance instructions in the guide {% endhint %}

Format external drive

Now, we will condition the external drive to create partitions. As a server installation, the Linux native file system Ext4 is the best choice for the external hard disk.

  • List all block devices with additional information. The list shows the devices (e.g. sda) and the partitions they contain (e.g. sda1)
lsblk -o NAME,MOUNTPOINT,UUID,FSTYPE,SIZE,LABEL,MODEL

Example of expected output without existing partitions:

NAME        MOUNTPOINT      UUID                                 FSTYPE     SIZE LABEL  MODEL
sda                                                                       931.5G        Ext_SSD
mmcblk0                                                                      58G
├─mmcblk0p1 /boot/firmware  4EF5-6F55                            vfat       512M bootfs
└─mmcblk0p2 /               ce208fd3-38a8-424a-87a2-cd44114eb820 ext4      57.5G rootfs

Example of expected output with existing partitions:

NAME        MOUNTPOINT      UUID                                 FSTYPE     SIZE LABEL  MODEL
sda                                                                       931.5G        Ext_SSD
└─sda1                      3aab0952-3ed4-4652-b203-d994c4fdff20 ext4     931.5G
mmcblk0                                                                      58G
├─mmcblk0p1 /boot/firmware  4EF5-6F55                            vfat       512M bootfs
└─mmcblk0p2 /               ce208fd3-38a8-424a-87a2-cd44114eb820 ext4      57.5G rootfs
  • Type this command to use the "fdisk" utility and manage the disk
sudo fdisk /dev/sda

-> 2 cases, depending on whether your drive contains partitions or not:

{% tabs %} {% tab title="Case 1: doesn't contain existing partitions" %} If you didn't see any "sdaX" partition in the previous step, i.e sda1:

  • Press "n" to create a new partition and then press ENTER until the prompt shows you: 
Created a new partition X of type 'Linux filesystem'
(Command (m for help)) again

{% endtab %}

{% tab title="Case 2: contain existing partitions" %} If you did see an existing partition "sdaX" in the previous step, i.e sda1:

  • Press "d" to delete the existing partitions and then press ENTER until the prompt shows you:
Partition X has been deleted
(Command (m for help)) again

{% hint style="info" %} If you have more than one partition, repeat the before step until there are none left {% endhint %}

  • Press "n" to create a new partition and then press ENTER until the prompt shows:
Created a new partition X of type 'Linux filesystem'
(Command (m for help)) again

{% endtab %} {% endtabs %}

-> Finally, don't forget, to type w and ENTER to write table to disk and exit

{% hint style="info" %} This will create a new partition called probably "sda1" -> Take note of this reference for the next step {% endhint %}

  • Format the partition on the external drive with the Ext4 system file (replace[NAME] to your partition name, e.g. sda1)
sudo mkfs.ext4 /dev/[NAME]

{% hint style="danger" %} Attention: this will delete all existing data on the external drive! {% endhint %}

Example of command:

sudo mkfs.ext4 /dev/sda1

Example of expected output:

mke2fs 1.46.5 (30-Dec-2021)
Creating filesystem with 1572608 4k blocks and 393216 inodes
Filesystem UUID: dafc3c67-c6e5-4eaa-8840-adaf604c85db
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736

{% hint style="info" %} Take note of the Filesystem UUID -> i.e: dafc3c67-c6e5-4eaa-8840-adaf604c85db, you will need this more later {% endhint %}

Mount external drive

The external drive is then attached to the file system and becomes available as a regular folder (this is called “mounting”).

  • List the block devices one more time to ensure that UUID has been assigned
lsblk -o NAME,MOUNTPOINT,UUID,FSTYPE,SIZE,LABEL,MODEL

Example of expected output:

NAME        MOUNTPOINT      UUID                                         FSTYPE       SIZE LABEL  MODEL
sda                                                                                 931.5G        Ext_SSD
└─sda1                      3aab0952-3ed4-4652-b203-d994c4fdff20      ext4     931.5G
mmcblk0                                                                                58G
├─mmcblk0p1 /boot/firmware  4EF5-6F55                                       vfat      512M  bootfs
└─mmcblk0p2 /               ce208fd3-38a8-424a-87a2-cd44114eb820            ext4      57.5G rootfs

{% hint style="info" %} Copy the new partition UUID into a text editor on your regular machine {% endhint %}

  • Edit the fstab file
sudo nano /etc/fstab
  • Add the following as a new line at the end of the file
UUID=<yourUUID> /data ext4 rw,nosuid,dev,noexec,noatime,nodiratime,auto,nouser,async,nofail 0 2

{% hint style="info" %} Replace <yourUUID> with your UUID obtained before {% endhint %}

  • Create the data directory as a mount point
sudo mkdir /data
  • Assing to the admin user as the owner of the /data folder
sudo chown admin:admin /data
  • Make the directory immutable to prevent data from being written on the microSD card if the external drive is not mounted
sudo chattr +i /data
  • Mount all drives
sudo mount -a
  • Check the file system. Is /data listed?
df -h /data

Example of expected output:

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda1       938G   77M  891G   1% /data

Or check the mount point using lsblk

lsblk -o NAME,MOUNTPOINT,UUID,FSTYPE,SIZE,LABEL,MODEL

Example of expected output:

NAME        MOUNTPOINT     UUID                                 FSTYPE   SIZE LABEL  MODEL
sda                                                                    931.5G        Ext_SSD
└─sda1      /data          15af9b1d-ca7c-441f-b101-c1a0cf76a062 ext4   931.5G
mmcblk0                                                                   58G
├─mmcblk0p1 /boot/firmware 4EF5-6F55                            vfat     512M bootfs
└─mmcblk0p2 /              ce208fd3-38a8-424a-87a2-cd44114eb820 ext4    57.5G rootfs

Resize & move the swap file to the new drive

The swap file acts as slower memory and is essential for system stability. microSD cards are not performant and degrade over time under constant read/write activity. Therefore, we move the swap file to the external drive and increase its size.

  • Edit the dphys-swapfile configuration file
sudo nano -l +12 /etc/dphys-swapfile
  • Uncomment the entry CONF_SWAPSIZE by deleting the # in front of it, and editing to match this
CONF_SWAPFILE=/data/swapfile
  • Comment on the entry CONF_SWAPSIZE by placing a "#" symbol in front of it. Save and exit
#CONF_SWAPSIZE=512

{% hint style="info" %} It will then be created dynamically to use ½ of the total RAM size installed {% endhint %}

  • Recreate and activate new swapfile
sudo systemctl restart dphys-swapfile
  • Check the new swap size
swapon --show

Example of expected output:

NAME           TYPE SIZE USED PRIO
/data/swapfile file   2G   0B   -2

Continue with the guide

{% hint style="success" %} That’s it: your Raspberry Pi now boots from the microSD card while the data directory /data is located on the external drive.

-> You can now continue with the Security section <- {% endhint %}