diff --git a/data.c b/data.c
index a55885d..e402a0e 100644
--- a/data.c
+++ b/data.c
@@ -15,10 +15,10 @@
 #include <sys/file.h>
 #include <fcntl.h>
 
-double db_layout = 2.7;
+double disk_layout = 2.7;
 
 
-int db_upgrade(d_char **error);
+int snac_upgrade(d_char **error);
 
 int srv_open(char *basedir, int auto_upgrade)
 /* opens a server */
@@ -71,9 +71,9 @@ int srv_open(char *basedir, int auto_upgrade)
                 }
 
                 if (auto_upgrade)
-                    ret = db_upgrade(&error);
+                    ret = snac_upgrade(&error);
                 else {
-                    if (xs_number_get(xs_dict_get(srv_config, "layout")) < db_layout)
+                    if (xs_number_get(xs_dict_get(srv_config, "layout")) < disk_layout)
                         error = xs_fmt("ERROR: disk layout changed - execute 'snac upgrade' first");
                     else
                         ret = 1;
diff --git a/snac.h b/snac.h
index 1678e86..ecf47a4 100644
--- a/snac.h
+++ b/snac.h
@@ -5,7 +5,7 @@
 
 #define USER_AGENT "snac/" VERSION
 
-extern double db_layout;
+extern double disk_layout;
 extern d_char *srv_basedir;
 extern d_char *srv_config;
 extern d_char *srv_baseurl;
diff --git a/upgrade.c b/upgrade.c
index 19fc39a..1b735c2 100644
--- a/upgrade.c
+++ b/upgrade.c
@@ -11,7 +11,7 @@
 #include <sys/stat.h>
 
 
-int db_upgrade(d_char **error)
+int snac_upgrade(xs_str **error)
 {
     int ret = 1;
     int changed = 0;
@@ -23,10 +23,10 @@ int db_upgrade(d_char **error)
 
         f = nf = xs_number_get(layout);
 
-        if (!(f < db_layout))
+        if (!(f < disk_layout))
             break;
 
-        srv_log(xs_fmt("db_upgrade %1.1lf < %1.1lf", f, db_layout));
+        srv_log(xs_fmt("disk layout upgrade needed (%1.1lf < %1.1lf)", f, disk_layout));
 
         if (f < 2.0) {
             *error = xs_fmt("ERROR: unsupported old disk layout %1.1lf\n", f);
@@ -294,14 +294,14 @@ int db_upgrade(d_char **error)
             xs *nv     = xs_number_new(f);
             srv_config = xs_dict_set(srv_config, "layout", nv);
 
-            srv_log(xs_fmt("db_upgrade converted to version %1.1lf", f));
+            srv_log(xs_fmt("disk layout upgraded to version %1.1lf", f));
             changed++;
         }
         else
             break;
     }
 
-    if (f > db_layout) {
+    if (f > disk_layout) {
         *error = xs_fmt("ERROR: unknown future version %lf\n", f);
         ret    = 0;
     }
@@ -316,7 +316,7 @@ int db_upgrade(d_char **error)
             fwrite(j, strlen(j), 1, f);
             fclose(f);
 
-            srv_log(xs_fmt("upgraded db %s after %d changes", fn, changed));
+            srv_log(xs_fmt("disk layout upgraded %s after %d changes", fn, changed));
         }
         else
             ret = 0;
diff --git a/utils.c b/utils.c
index 5639aa0..4bc1b01 100644
--- a/utils.c
+++ b/utils.c
@@ -103,7 +103,7 @@ int initdb(const char *basedir)
 
     srv_config = xs_json_loads(default_srv_config);
 
-    xs *layout = xs_number_new(db_layout);
+    xs *layout = xs_number_new(disk_layout);
     srv_config = xs_dict_set(srv_config, "layout", layout);
 
     printf("Network address [%s]:\n", xs_dict_get(srv_config, "address"));