File dirty.fl prevent me from backup

Hello,

i’m using orientdb in my project.
I want to create backup of my data/ directory while my project is running, but I got errors on copying this type of files “dirty.fl”.

Are they absolutely needed in a backup? What is their purpose ?

I’m on windows, using Time Navigator to backup, but anyway, the copy fails even when i’m trying to do it manually.

Thanks for your time

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