Backup or snaphot tool for ext4

I'm looking for a backup tool for ext4, which can take a copy from a running fs like /var with no collisi开发者_如何学Pythonons after recover such fs. I know BSD dump has an '-L' option, which tells him to work on a snapshot. But nor dump nor dumpe2fs from repository have such option. I've read about a patchset for ext4 providing snapshot support, but replies about it are very different, so i'm here to ask about your experience with this patches.

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It's not a dump tool but I use rsync which allows incremental backups between 2 filesystems on a running system.

for example rsync -aSXvH /srcdir /target_dir