Restore files on Raspberry Pi SD card remotely

Question

I usually remove the SD cards and use the balenaEtcher to format and rewrite my previously backed-up image from my laptop to Raspberry Pi.

Is there a way to do this job or at least restore an entire folder remotely?

By the way, I can not copy files to some folders of the Raspberry Pi due to access permissions.

Answer 1

If you want to keep a backup image updated rather easily, you should try image-backup - a component of image-utils. image-backup allows you to create an image file backup of your entire system using a simple one-line command:

$ sudo image-backup 

The output is an image file (.img) which can be saved to any file system you can mount on your RPi.

As an image file, you can do things with it:

1. It can be written to an SD card using BalenaEtcher - or any of a number of other programs. In other words, you can restore your entire system to an SD card, and then boot from it.
2. You can mount this image file from your RPi (and other systems), and access any file or folder in it (e.g. restore an entire folder remotely).

Updating this image file with image-backup is very easy: Running image-backup with a parameter of an existing image filename will incrementally update that image file; e.g.:

$ sudo image-backup /path/to/existing/backup.img 

Perhaps the best feature of image-backup is that it uses rsync, which is much more efficient than dd.

If you're interested, there's another answer here that covers the installation, and a step-by-step for creating an image.

Answer 2

On first read I assumed you were using dd to create the images and balenaEtcher to restore -- until it was pointed out you probably used the latter for both tasks. So: Below I'm referring to two different methodologies regarding backup, one the "blob image" I've associated with dd (but also applies to what balenaEtcher does), and the other "file based", which is what I'm recommending.

It [was upon first read ;)] implicit in this you are using dd to keep a backup (but if you are using balenaEtcher, it is much the same thing in terms of the image format). While this is very easy to do, it is very inflexible (as well as being wasteful resource wise, ie., takes a long time and uses a lot of bandwidth).

Is there a way to do this job

There is not an existing one that I'm aware of using a blob image copy (as from dd), and although it would not be impossible to implement one, that is going to be a mountain more headache and effort than just using a backup methodology that is intended to be usable live remotely, such as rsync.

or at least restore an entire folder remotely?

This is a bit of a distinct issue. Using a system that copies files (such as rsync or tar) instead of raw blocks (such a dd), it is pretty simple and self-explanatory once you understand the methodology.¹

It is also possible using a blob image, but not really worthwhile because you will have to use a file-based method for the restore, by mounting the image somewhere and copying them from there. Since you could count "the root filesystem" as "a folder", you could do this with /, but that is going to be the most ponderous, inefficient, and error prone choice of all.

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1. Which I won't bother with because you will find decades worth of examples, tutorials, how-tos, etc. regarding rsync or tar, online, including here.