+// ========================
+// Internal data structures
+//
+// These global variables are used by multiple parts of the
+// program. They are good candidates for moving into their own
+// packages.
+
+// The Keep VolumeManager maintains a list of available volumes.
+// Initialized by the --volumes flag (or by FindKeepVolumes).
+var KeepVM VolumeManager
+
+// The pull list manager and trash queue are threadsafe queues which
+// support atomic update operations. The PullHandler and TrashHandler
+// store results from Data Manager /pull and /trash requests here.
+//
+// See the Keep and Data Manager design documents for more details:
+// https://arvados.org/projects/arvados/wiki/Keep_Design_Doc
+// https://arvados.org/projects/arvados/wiki/Data_Manager_Design_Doc
+//
+var pullq *WorkQueue
+var trashq *WorkQueue
+