Image from sd card linux

How to create an .IMG image of a disc (sd card) without including free space?

In Linux, we can do

but if the disk is of 32GB with only 4GB used, the 32GB image file is waste of space-time. Is there any way or tool to create images with only valid data?

7 Answers 7

Pretty good and simple way to deal with this is simply pipe it via gzip, something like this:

This way your image will be compressed and most likely unused space will be squeezed to almost nothing.

You would use this to restore such image back:

One note: if you had a lot of files which were recently deleted, image size may be still large (deleting file does not necessarily zeroes underlying sectors). You can wipe free space by creating and immediately deleting large file containing zeros:

The best thing to do is

Copy all the files from all the partitions preserving meta data

mkdir -p myimage/partition1

sudo cp -rf —preserve=all /media/mount_point_partition1/* myimage/partition1/

sudo cp -rf —preserve=all /media/mount_point_partition2/* myimage/partition2/

Extract the MBR

sudo dd if=/dev/sdX of=myimage/mbr.img bs=446 count=1

replace /dev/sdX with the corresponding device.

Partition the destination disk into partitions with sizes greater than copied data and should be of the same format and same flags using gparted . Google how to partition a disk.

Mount the freshly formatted and partitioned disk. On most computers, you just need to connect the disk and you can find the mounted partitions in /media folder.

Copy the previously copied data to destination partitions using following commands

sudo cp -rf —preserve=all myimage/partition1/* /media/mount_point_partition1/

sudo cp -rf —preserve=all myimage/partition2/* /media/mount_point_partition2/

Copy back the MBR

sudo dd if=myimage/mbr.img of=/dev/sdX bs=446 count=1

Now njoy Ur new disk!

Using the bs and count parameters of dd , you can limit the size of the image, as seen in step 2 of answer 1665017.

You may already know what size image you want to create. If not, you can get a good idea from df :

Substitute / with a space-separated list of all the mount points relating to the disk partitions.

A more accurate way might be to use fdisk or your preferred partition editor and get busy with a calculator.

Total used space in bytes = end sector of last partition X sector size (here that’s 3667967 x 512).

Total used space in GB = total used space in bytes / 1024 3 (here that’s 1.749023 GB).

If you decide, for example, that your image should be exactly 2 GB, the following command will do that:

The resulting image will also include the random noise beyond the greatest extent of the last partition.

Don’t forget to sudo the above commands if your account doesn’t already have sufficient privileges.

For my purposes, I don’t need an image that is perfectly trimmed down to the last bit of data so when the real size is 1.75 GB then a 2 GB image is near enough for me. This cuts out the other 6 GB (or 30 GB or whatever the device has spare) of unused space that would otherwise be in the image.

I have seen advice in many places that dd should not be performed on a mounted partition and I followed that because it seems intuitively correct; it does seem rather like trying to sketch yourself making a sketch in a mirror with the sketch you’re making also visible in the sketch. It’s a bit sketchy.

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How do I make an ISO from a working SD card?

I have this frankenstein Linux, that works on a specific device that multiple people use in a forum. I have found a way to improve upon the work of someone on the forum, who shared his ISO, and want to share my image to that creator of this original ISO file.

The ISO doesn’t need to include installation files. It’s just a working Linux partition with a boot partition. Can I just do:

Or do I need to approach it from another angle?

2 Answers 2

Yes, the command you’re thinking of will certainly produce a disk image file that can be written to another similar disk. But calling it an ISO file will only make sense if the disk actually contains an ISO9660 filesystem intended to be burned on a CD-ROM or DVD. The ISO9660 standard and its extensions define a procedure for booting from a CD-ROM that is significantly different from how booting is handled on hard-disk-like media. The newer UDF filesystem specification is much the same, but for larger-capacity and/or rewritable optical media.

Many modern Linux ISO images now have the feature that they can also be written to a hard-disk-like media (e.g. USB stick, SD card or similar) and they will be bootable — but that has actually nothing at all to do with the ISO9660 filesystem format. These images have gone through an additional isohybrid process that adds an extra hard-disk-like partition table to the ISO image, allowing the same image file to support two different kinds of boot processes: one for hard-disk-like media, and another for optical media.

Calling something an ISO image file carries with it an implicit promise that you can burn it to a CD-ROM, DVD or Blu-Ray and it will produce a working optical disk. If that is not actually the case (i.e. the filesystem type used is neither ISO9660 nor UDF, or it contains a partition table and multiple partitions), then you should not use the .iso suffix, but instead .img or .ima . These suffixes are recognized as more general «disk or filesystem image files», and don’t include any implicit claim about being related to optical discs at all.

Yes, this is just a minor nitpick, but it’s a pet peeve of mine.

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Как сделать резервную копию SD-карт и флеш-накопителей в Linux с помощью DD

от sasza

Резервное копирование портативных вещей, таких как SD-карты и USB-накопители, в Linux проще, чем кажется, и это можно сделать прямо из терминала, используя инструмент DD copy and convert. DD действительно универсален, и с его помощью пользователи могут копировать большие объемы данных из одного места в другое. Достаточно сказать; Инструмент DD имеет множество применений. Одно из лучших применений — резервное копирование хранилища данных. В прошлом в toadmin.ru мы использовали этот метод для создания копий жестких дисков. Его также можно использовать для резервного копирования SD-карт и флэш-накопителей. Вот как это работает.

ОПОВЕЩЕНИЕ СПОЙЛЕРА: прокрутите вниз и посмотрите видеоурок в конце этой статьи.

Резервное копирование SD-карт и флэш-накопителей

Для начала откройте окно терминала и подключите SD-карту / USB-накопитель, для которого вы пытаетесь создать резервную копию. Используйте команду lsblk для печати всех доступных устройств в системе.

Имейте в виду, что SD-карты не будут соответствовать общей структуре / dev / sdX, особенно если вы используете встроенный считыватель карт памяти. Вместо этого вы должны увидеть / dev / mmcblk, за которым следует информация о разделе.

Примечание. Резервное копирование USB должно осуществляться по традиционной схеме именования / dev / sdX.

Ваша SD-карта может не отображаться как / dev / mmcblk (или аналогичный), если вы используете USB-адаптер. Название метки устройства зависит от того, как адаптер SD-карты работает с Linux. Лучше всего прочитать руководство к адаптеру.

После того, как вы определились с меткой, вам нужно точно выяснить, как вы пытаетесь сделать резервную копию. Выберите метод ниже, который подходит для вашего варианта использования.

Резервное копирование файла изображения

Первый метод резервного копирования с помощью DD — использовать его для сохранения всего в простой файл образа. Для этого вам нужно будет ввести следующую команду. Имейте в виду, что процесс создания образа займет много времени, особенно если у вас есть большая SD-карта или USB-накопитель.

USB-накопители

Выполнение этой команды приведет к созданию полной копии USB-накопителя и сохранению ее в файле с именем image-of-usb.img. Возьмите этот файл изображения и сделайте резервную копию в безопасном месте. Если вы хотите повысить безопасность, выполните следующие действия, чтобы зашифровать его с помощью GnuPG.

Вывод GnuPG должен быть image-of-usb.img.gpg.

После завершения процесса шифрования удалите исходный файл и сохраните зашифрованный.

Извлеките изображение из зашифрованного файла в любое время с помощью:

SD-карты

Примечание: 0 означает SD 1.

Выполнение этой команды DD сделает снимок вашей SD-карты и сохранит его в файл в файловой системе с именем image-of-sd-card.img. Вы сможете переместить этот архивный образ, загрузить его в Dropbox, Google Drive, на домашний сервер и т. Д. Имейте в виду, что этот архив небезопасен, и к конфиденциальным данным можно легко получить доступ, если кто-то получит их. Вот почему мы рекомендуем вам также зашифровать резервную копию SD с помощью GnuPG.

Чтобы зашифровать, выполните эту команду:

Шифрование должно выводить файл с меткой image-of-sd-card.img.gpg

Вы должны удалить исходный исходный файл, когда шифрование завершится.

Чтобы извлечь зашифрованный архив, повторно запустите gpg без -c.

Дубликаты USB и SD карт

Если вы предпочитаете создать копию SD-карты, а не создавать резервную копию всего изображения, следуйте этим инструкциям. Первый шаг — подключить как SD / USB, для которого вы хотите создать резервную копию, так и второй SD / USB, который вы будете использовать в качестве приемника дублирования. Затем используйте команду lsblk для вывода списка устройств. Найдите все ярлыки устройств и запишите их.

Например, чтобы скопировать SD-карту 1 на SD-карту 2, мне нужно будет использовать / dev / mmcblk0 и / dev / mmcblk1. Еще раз обратитесь к lsblk –help, если необходимо.

Когда вы придумали правильные метки, следуйте приведенным ниже инструкциям.

USB-накопители

Команда, которую мы использовали ранее для сохранения USB в образ, может работать в этой ситуации. Единственное, что меняется, — это аспект команды «of =». Вместо того, чтобы выводить его на of =

/ image-of-usb.img, мы будем выводить его на второй USB-накопитель.

В этом примере флэш-накопитель USB №1 — это / dev / sdc, а флэш-накопитель USB №2 — это / dev / sdd. Ваш может отличаться.

По завершении DD все данные с диска №1 должны находиться на диске №2!

SD-карты

Как и в разделе USB, DD берет данные с SD-карты №1, дублирует их и помещает на SD-карту №2. Запишите эту команду в терминал, чтобы запустить процесс дублирования. В этом примере SD-карта №1 будет / dev / mmcblk0, а №2 будет / dev / mmcblk1.

Вы узнаете, что процесс завершен, когда терминал снова сможет принимать текст с клавиатуры.

Восстановление резервных копий

Самый быстрый способ восстановить резервный образ DD на SD-карту или USB-накопитель — просто прошить его с помощью инструмента Etcher. Использование этого инструмента для восстановления данных может показаться немного странным, поскольку Etcher в основном предназначен для записи образов ОС, но он работает очень хорошо!

Начните с загрузки последней версии Инструмент для прошивки Etcher для Linux откройте его и вставьте USB-накопитель или SD-карту.

В программе Etcher нажмите «Выбрать изображение», чтобы открыть окно выбора изображения. В этом окне найдите файл image-of-sd-card.img или image-of-usb.img и выберите его. Когда изображение загрузится, нажмите «Flash» и начните восстановление!

Когда Etcher показывает окно конечного экрана, ваши данные должны быть на устройстве.

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How to Create an Image of a Raspberry Pi SD Card? (Win/Linux/Mac)

Creating an entire image of your SD card can be really useful on Raspberry Pi. The system and your data are on this little piece of plastic, which isn’t the safest :).
In this tutorial, I’ll show you how to make a full backup copy of your SD card (system, configuration and data).

For a Raspberry Pi with many data or even critical data, it’s a good practice to create an image of the entire storage.
On Windows, Win32 Disk Imager is the best tool to do this.
On Linux, the dd command can do this. And on macOS, ApplePi Baker is the best choice for a graphical solution.

Here it is for the short answer, but these tools are not easy to use for the first time. So, in this guide I’ll show you step-by-step how to do in each case.
But before that, we’ll start by a short explanation on why it’s so important to do this from time-to-time, if you aren’t sure yet.

If you are looking for quick progress on Raspberry Pi, you can check out my e-book here. It’s a 30-day challenge, where you learn one new thing every day until you become a Raspberry Pi expert. The first third of the book teaches you the basics, but the following chapters include projects you can try on your own.

Why do you need to create a Raspberry Pi image?

If you are on this page, there is a good chance you already know why you want to create an image of your Raspberry Pi.
But you may not have considered all benefits of this procedure. Below is a quick list of reasons or cases to help you.

Your SD card will stop working

The first thing to consider is the storage you are using on Raspberry Pi.
As your system and critical data are on a micro SD card, don’t expect to keep years for life in the same state.

The lifespan of a SD card is expected to be 10 years or more. But, this mostly depends on the model, the usage and how you handle it daily. Even if you use the best SD card with your Raspberry Pi, it may still happen.
If you use your SD card with caution, always in the same device, with a low disk usage on your Raspberry Pi, it could have a long lifespan. But if you change devices regularly, travel a lot or let your Raspberry Pi run on heavy load all day, it probably won’t.

Also, your system may be corrupted one day, due to updates, security breaches or mishandling.

In short, don’t expect your SD card to work forever, and anticipate a malfunction at anytime.

A solid backup is mandatory

Basically, I never expect a storage method to be 100% safe.
That’s why I recommend doing regular backups of them if you keep critical data on your card.

I already have an entire guide on how to back up your Raspberry Pi.
And today, we’ll see how to clone the entire SD card on your computer.
This is the best way if you have a lot of critical or important data.

By the way, even if you have a retro gaming solution like Retropie on it and think you don’t need to be concerned, think again. If there is a huge catalog of games on your Raspberry Pi, I really recommend backing up your SD card :).

A copy on your computer or on an external drive (I recommend this one) will be worth it if you spend a lot of time on your Pi.

Use this technique to save time

Small anecdote here, when I started on Raspberry Pi, I tested 5 to 10 new projects each week (while writing my experiences on RaspberryTips).
SD card preparation, update and configurations (like Wi-Fi and keyboard layout) was a waste of time for me.

My solution was to create a basic Raspbian installation on a small SD card, and create an image on my computer.
This way, I could flash this image instead of the one from the Raspberry Pi Foundation and everything would be ready to use.

I have learned a lot and generally use the configuration files to do this. I have the files on my computer, and I copy them to each SD card I flash (you can learn how to do this in this article). In the beginning this was very useful.
Even so, there are probably many cases where it makes sense to do this (cluster? Multiple web servers? Many Raspberry Pi deployment?).

Create an image on Windows

As most of you are generally on Windows, let’s start with this system.

Win32 Disk Imager

Win 32 Disk Imager is a well-known tool on Windows for Raspberry Pi And Linux users.
It’s often used to create SD cards (or USB disk) from an image of an operating system downloaded on the Internet.

You can download it here on SourceForge.
It looks like this:

But the goal today is the opposite: creating an image from an SD card.
Win 32 Disk Imager can also do this, let’s see how!

Step-by-step image creation with Win32 Disk Imager

Here are the steps to follow to create an image of any SD card on Windows, with Win 32 Disk Imager:

• Insert your SD card in your computer.
  If you don’t have an SD card reader on your computer, you’ll need a USB adapter for this (I explain everything here).
• Find the partition letter corresponding to your SD card: Open the File explorer and go to “This PC”.

Take note of the drive letter, you’ll need it later.

Open Win 32 Disk Imager.

Start by choosing an image location and name for your image:

Make sure to have enough free space on your disk where you want to store the image (a 64 GB SD card can quickly fill a SSD disk ^^).
You can use a local storage, or an external USB drive.
Then select the device you want to back up:

You’ll typically only see the “boot” partition, but don’t worry, Win32DiskImager will create an entire image of all partitions on the device.

You can now click on “Read” to start the copy:

The process will start and it can take some time depending on your SD card size (between 15min and 1h in general for a standard size):

Once done, your image is safe, and we’ll now see how to flash it on another card.

Restoring the image to any SD card

I recommend doing at least one test to recover the SD card from this image before considering you are safe.
I have had too many backups in my life that didn’t work when needed, so we can never be sure if a backup will work in real conditions :).

What you can do, is insert another SD card in your computer and flash it with the image.
To do this, you can use Win32 Disk Imager almost the same way:

• Choose the image file.
• Pick the device letter in the list.
• And click on “Write” to start the copy:

If you prefer, there are other tools to do the same thing.
The one I recommend everywhere on this website is Etcher. You can also use Raspberry Pi Imager if you want (official software from the Raspberry Pi Foundation). By the way, you can also install Raspberry Pi Imager on RPI OS if you don’t have a computer.

Create an image on Linux

If you are a Linux user, let’s see how to do this on your favorite system!
I’ll show you on Ubuntu, but the tool is the same on any distribution.

The dd command

“dd” is a base command on Unix. The goal is to offer a tool to manage files.
You can use it to erase a partition (filling it with zeros), generate a random file, but also to manage disk images!
I’m also using it for benchmarks (like in this post about SD cards).

As dd can do a complete backup of any disk, it’s really useful for this.
Let’s see how to use it!

A bit lost in the Linux command line? Check this article first, which will give you the most important commands to remember and a free cheat sheet you can download to have them all at your fingertips.

How to use “dd” to back up the SD card

Find the device name

Looking for the drive letter on Windows is pretty easy, but on Linux it’s a bit more hidden.
A device name on Linux is something like /dev/sdX (if you use an USB adapter), or /dev/mmcblkX (if your computer has an SD card reader).

On Ubuntu, you can use the Disk Utility to find this information:

I’m using a 16 GB SD card for this test, so this is this one (/dev/sde).
If you aren’t on Ubuntu and can’t find a similar tool, you can also jump to the terminal and use the following command:
sudo fdisk -l

It will show you a list of drives on your computer. You just need to find the one corresponding to your SD card.
In my case, it looks like this:

So, we have a disk named /dev/sde, with two partitions (/dev/sde1 and /dev/sde2).

Create the image with dd

Once we know the device name, we need the correct command to create the image of this device:

• Open a terminal.
• Type the following command:
  sudo dd bs=4M if=/dev/sde of=/home/username/MyImage.img
• Don’t forget to replace the device name (if for input file) and the file destination (of for output file).
• You’ll get something like this:

Expect at least 15 minutes to create the image (depending on the SD card size).

Image restoration to the SD card

Copying back the image to another SD card is almost the same thing.
I recommend trying this at least one time, just to be sure that your image is working (don’t try on the same SD card!).

To copy an image to a new SD card, there are two ways you can use:

• The first one is to use dd again, in the reverse order:
  • The command is something like:
    sudo dd bs=4M if=/home/username/MyImage.img of=/dev/sde
  • For the first time, you need to edit this command with the correct path, image name and device name.
• The second way, that I always recommend is to use Etcher:
  • Etcher is a free tool you can download here.
    The good news is that it’s a graphical tool and very intuitive.
    The dd command seems simple now because you just used it to create the image, but in 6 months, you probably won’t remember the correct options.
  • The tool looks like this:

    Just select your backup image, your drive (automatic in theory), and click on “Flash!” to start the copy.

Whatever the method you use, it should create an exact replica of the original SD card.
Once done, insert it in your Raspberry Pi and check that everything is working correctly.

Create an image on macOS

The last operating system is macOS.
I will be quick on this tutorial, as I didn’t test because I don’t have a Mac :).
But I know they are working methods to create an image from your Raspberry Pi.

First method: use dd

The first method is to use “dd”, like in the previous part for Linux.
As macOS is based on Unix, dd is also available on it.

Just run a terminal and follow the Linux part :).

Second method: try ApplePi Baker

If you prefer a graphical tool, I found ApplePi Baker that seems to do exactly what we need.
You can download it here on Tweaking4All.
Scroll down to the ApplePi-Baker V2 download link, get it and install it:

The tool looks like this:

It’s intuitive, with big symbols for each step.
Start by choosing the disk you want to back up on the left, then click on “Backup” to set the image name and location.
Once done, the process starts, and your image is created as with dd.

Restoration on macOS

As on any operating system, it’s mandatory to try your backup at least once before considering the job done.
What you can do, is to take a new SD card and flash the image to it, then test it on your Raspberry Pi

I already explained in the Linux part two ways you can use: dd and Etcher. They will work perfectly on macOS.
If you want to use these tools, go to the previous part about Linux and find the “Image restoration” section.

The other way if you installed ApplePi-Baker, is to use the “Restore” option on the right.
Pick the disk you want to flash (“1” on my picture), and click on “Restore” to select the image to copy.
The process will starts immediately. After a few minutes, try to boot this SD card on your Raspberry Pi, and see how it goes.

If everything is OK, you can consider your backup safe.
Redo the same process regularly to keep an updated version of the image (if needed).

Video

Conclusion

That’s it, you now know why you should create an image of a Raspberry Pi, and how to do so on any operating system.
I hope this guide was useful for you, if it’s the case, please share it on your favorite social network!

Don’t forget this technique, even if you don’t need it yet. It will save you a lot of time in the future if you remember to create images for your most critical systems.
By the way, try to keep the image at a safe location too (or keep two copies), your computer disk can also break or be formatted :).

A good external hard drive (my favorite is this one on Amazon) is probably a good option to consider. Personally, I’m using a NAS at home for all these backups (this one from Synology), but that’s a bit more expensive.

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