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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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Automatic backups of inode tables and partition info for easier data recovery (lemmy.nz)

submitted 11 months ago* (last edited 11 months ago) by luthis@lemmy.nz to c/linux@lemmy.ml

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Good morning all, in today's episode of "What I learned during work hours"...

I was playing around with wxHexEditor and realised that if something catastrophic happened, I would really struggle with any data recovery if I lost the inode tables for any drive.

A quick duckle pointed me to e2image, which says in the man:

It is a very good idea to create image files for all file systems on a system and save the partition layout (which can be generated using the fdisk -l command) at regular intervals

at boot time, and/or every week or so.

I couldn't find any prebuilt solutions for this online, so I wrote a systemd service and timer to do this for me. I save the fdisk to a text file, run e2image on a couple drives, and compress it all together in a dated 7z that can get uploaded via rsync or Mega or Dropbox etc.

The metadata image from a 500gb drive is 8gb, but compresses down to 40mb. Backup takes a couple minutes.

~~Unfortunately this does not work with my raid drives, but they are RAID1 so already resilient.~~

Apparently I was being a derp somehow. ...Anyways,

My RAID drives are 16TB, e2image of this is 125gb, and 7z'd it comes down to just 63mb.

I'll post the service, timer, and backup script in a comment, let me know if you can spot anywhere for improvements!

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[–] luthis@lemmy.nz 1 points 11 months ago (1 children)

For fun and learning. It's just another tool to go with file level backup.

And the backup for this is 40mb and really fast, but backing up files even when compressed would be hundreds of GB, maybe terabytes, and then you're paying for that amount of storage online somewhere, uploading for hours..

[–] Quazatron@lemmy.world 1 points 11 months ago

Picture this: you open and edit one of your documents and save it.

The filesystem promptly allocates some blocks and updates the inodes. Maybe the inode table changed, maybe not. Repeat for some other files. Now your "inode backup" has a completely different picture of what is going on on your disk. If you try to recover the disk using it, all you will achieve is further corruption of the filesystem.