Is there a CPU/RAM overhead associated with using loop-mounted images versus using a physical partition under Linux?
Linux – Overhead of Using Loop-Mounted Images
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linuxloop-device
Is there a CPU/RAM overhead associated with using loop-mounted images versus using a physical partition under Linux?
Best Answer
Yes, unless you have a very recent kernel there is significant overhead when using loop devices on linux: data accessed through the loop device has to go through two filesystem layers, each doing its own caching so data ends up cached twice, wasting much memory (the infamous "double cache" issue)
Aside from casual use better alternatives would be to use a dedicated partition or a chroot so data can be accessed directly.
Or use latest kernel, the issue is fixed in linux 4.4 and newer: