lmdb.h Caveats: Reserved vs. actual mem/disk usage

diff --git a/libraries/liblmdb/lmdb.h b/libraries/liblmdb/lmdb.h
index 98e8c51..f684da7 100644 (file)
--- a/libraries/liblmdb/lmdb.h
+++ b/libraries/liblmdb/lmdb.h
@@ -78,6 +78,11 @@
  *       access to locks and lock file. Exceptions: On read-only filesystems
  *       or with the #MDB_NOLOCK flag described under #mdb_env_open().
  *
+ *     - An LMDB configuration will often reserve considerable \b unused
+ *       memory address space and maybe file size for future growth.
+ *       This does not use actual memory or disk space, but users may need
+ *       to understand the difference so they won't be scared off.
+ *
  *     - By default, in versions before 0.9.10, unused portions of the data
  *       file might receive garbage data from memory freed by other code.
  *       (This does not happen when using the #MDB_WRITEMAP flag.) As of