| 1234567891011121314151617181920212223242526272829303132333435363738394041 | .. _faq:.. include:: global.rst.incFrequently asked questions==========================Which platforms are supported?    Currently Linux, FreeBSD and MacOS X are supported.Can I backup VM disk images?    Yes, the :ref:`deduplication <deduplication_def>` technique used by |project_name|    makes sure only the modified parts of the file are stored.Which file attributes are preserved?    The following attributes are preserved:    * Name    * Contents    * Time of last modification (nanosecond precision with Python >= 3.3)    * User ID of owner    * Group ID of owner    * Unix Permission    * Extended attributes (xattrs)    * Access Control Lists (ACL_) on Linux, OS X and FreeBSD    * BSD flags on OS X and FreeBSDHow can I specify the encryption passphrase programmatically?    The encryption passphrase can be specified programmatically using the    `ATTIC_PASSPHRASE` environment variable. This is convenient when setting up    automated encrypted backups. Another option is to use    key file based encryption with a blank passphrase. See    :ref:`encrypted_repos` for more details.When backing up to remote servers, is data encrypted before leaving the local machine, or do I have to trust that the remote server isn't malicious?    Yes, everything is encrypted before leaving the local machine.If a backup stops mid-way, does the already-backed-up data stay there? I.e. does Attic resume backups?    Yes, during a backup a special checkpoint archive named ``<archive-name>.checkpoint`` is saved every 5 minutes    containing all the data backed-up until that point. This means that at most 5 minutes worth of data needs to be    retransmitted if a backup needs to be restarted.
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