diff --git a/data.c b/data.c
index 52e0f09..1633203 100644
--- a/data.c
+++ b/data.c
@@ -545,6 +545,9 @@ xs_list *index_list_desc(const char *fn, int skip, int show)
 
 xs_str *_object_fn_by_md5(const char *md5)
 {
+    if (!xs_is_hex(md5))
+        srv_log(xs_fmt("_object_fn_by_md5(): '%s' not hex", md5));
+
     xs *bfn = xs_fmt("%s/object/%c%c", srv_basedir, md5[0], md5[1]);
 
     mkdirx(bfn);
diff --git a/doc/snac.5 b/doc/snac.5
index 9afa68c..07c833d 100644
--- a/doc/snac.5
+++ b/doc/snac.5
@@ -89,6 +89,8 @@ including HTTP headers. Only useful for debugging. May grow to enormous sizes.
 .It Pa error/
 If this directory exists, HTTP signature check error headers are logged here.
 Only useful for debugging.
+.It Pa log/
+If this directory exists, log messages are also stored there in daily files.
 .It Pa app/
 This directory stores Mastodon API apps.
 .It Pa token/
diff --git a/snac.c b/snac.c
index 41e1984..7fbb61e 100644
--- a/snac.c
+++ b/snac.c
@@ -95,8 +95,9 @@ void srv_debug(int level, xs_str *str)
         xs *tm = xs_str_localtime(0, "%H:%M:%S");
         fprintf(stderr, "%s %s\n", tm, str);
 
-        /* if the ~/error/ folder exists, also write to a file there */
-        xs *lf = xs_fmt("%s/error/debug.log", srv_basedir);
+        /* if the ~/log/ folder exists, also write to a file there */
+        xs *dt = xs_str_localtime(0, "%Y-%m-%d");
+        xs *lf = xs_fmt("%s/log/%s.log", srv_basedir, dt);
         FILE *f;
         if ((f = fopen(lf, "a")) != NULL) {
             fprintf(f, "%s %s\n", tm, str);