> drop files content from page cache after closing, useful for backups It took me a minute to understand why this is useful for backups. It prevents your backu

> drop files content from page cache after closing, useful for backups It took me a minute to understand why this is useful for backups. It prevents your backup tool from leaving a bunch of stuff in cache that isn't needed. It's a performance thing. (And it's not a data integrity thing, which came to mind because one reason for flushing a cache is to be sure writes to the underlying layer been done.) This leads to an interesting question: do most backup tools not already have this optimization built in? From a quick perusal of the GNU tar manual page and source and running it under strace, it doesn't seem like it supports it. (Though tar is really more of an archive tool than a backup tool, which isn't precisely the same thing.)