Currently authentication must be done using ssh-agent. Other
authentication methods may be supported in future.
-Note: The ssh driver does not obey disk flush requests (ie. to commit
-data to the backing disk when the guest requests it). This is because
-the underlying protocol (SFTP) does not support this. Thus there is a
-risk of guest disk corruption if the remote server or network goes
-down during writes.
+Note: Many ssh servers do not support an @code{fsync}-style operation.
+The ssh driver cannot guarantee that disk flush requests are
+obeyed, and this causes a risk of disk corruption if the remote
+server or network goes down during writes. The driver will
+print a warning when @code{fsync} is not supported:
+
+warning: ssh server @code{ssh.example.com:22} does not support fsync
+
+With sufficiently new versions of libssh2 and OpenSSH, @code{fsync} is
+supported.
@node pcsys_network
@section Network emulation