Post Azc5MDl5UFUbkosKJc by dragoonaethis@mstdn.social
 (DIR) More posts by dragoonaethis@mstdn.social
 (DIR) Post #Azc5MDl5UFUbkosKJc by dragoonaethis@mstdn.social
       2025-10-26T21:12:46Z
       
       0 likes, 0 repeats
       
       TIL you can use the Linux device mapper to create a read-only overlay on an arbitrary block device: https://unix.stackexchange.com/questions/67678/gnu-linux-overlay-block-device-stackable-block-deviceSay you've got a HDD with a broken OS in an unknown/malware-riddled state. You want to boot and poke it in a VM, but without making things worse if shit happens. With dm you can set up an overlay device that passes through reads, accepts writes to a local COW file, but keeps the original device untouched. You can discard or write changes to the device after you're done.
       
 (DIR) Post #Azc5MF2qhhIJkCC1dg by wolf480pl@mstdn.io
       2025-10-26T21:19:56Z
       
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       @dragoonaethis yeah, this is how LVM snapshots work under the hood