FAQ: Why is backing up an unmodified FAT filesystem slow on Linux?

helmutg · Sep 23, 2024 · 8c444ba · 8c444ba
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 Use ``borg repo-compress`` to efficiently recompress a complete repository.
 
+Why is backing up an unmodified FAT filesystem slow on Linux?
+-------------------------------------------------------------
+
+By default, the files cache used by BorgBackup considers the inode of files.
+When an inode changes compared to the last backup, it hashes the file again.
+The ``vfat`` kernel driver does not produce stable inodes by default. One way
+to achieve stable inodes is mounting the filesystem using ``nfs=nostale_ro``.
+Doing so implies mounting the filesystem read-only. Another option is to not
+consider inodes in the files cache by passing ``--files-cache=ctime,size``.
+
 Security
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