diff --git a/kmod/src/btree.c b/kmod/src/btree.c
index 104b4e54..7fdb2b72 100644
--- a/kmod/src/btree.c
+++ b/kmod/src/btree.c
@@ -142,11 +142,10 @@ enum {
 /*
  * This greatest key value is stored down the right spine of the tree
  * and has to be sorted by memcmp() greater than all possible keys in
- * all btrees.  We give it room for a decent number of big-endian
- * primary sort values.
+ * all btrees.
  */
-static char max_key[SCOUTFS_BTREE_GREATEST_KEY_LEN] = {
-	[0 ... (SCOUTFS_BTREE_GREATEST_KEY_LEN - 1)] = 0xff,
+static char max_key[SCOUTFS_BTREE_MAX_KEY_LEN] = {
+	[0 ... (SCOUTFS_BTREE_MAX_KEY_LEN - 1)] = 0xff,
 };
 
 /* number of contiguous bytes used by the item header, key, and value */
@@ -1262,9 +1261,7 @@ static bool invalid_item(void *key, unsigned key_len, unsigned val_len)
 {
 	return WARN_ON_ONCE(key_len == 0) ||
 	       WARN_ON_ONCE(key_len > SCOUTFS_BTREE_MAX_KEY_LEN) ||
-	       WARN_ON_ONCE(val_len > SCOUTFS_BTREE_MAX_VAL_LEN) ||
-	       WARN_ON_ONCE(key_len > SCOUTFS_BTREE_GREATEST_KEY_LEN &&
-			    cmp_keys(key, key_len, max_key, sizeof(max_key)) > 0);
+	       WARN_ON_ONCE(val_len > SCOUTFS_BTREE_MAX_VAL_LEN);
 }
 
 /*
diff --git a/kmod/src/format.h b/kmod/src/format.h
index 27e467a5..29ea140c 100644
--- a/kmod/src/format.h
+++ b/kmod/src/format.h
@@ -121,15 +121,9 @@ struct scoutfs_key_be {
 	__u8	_sk_fourth;
 }__packed;
 
-/*
- * Assert that we'll be able to represent all possible keys with 8 64bit
- * primary sort values.
- */
-#define SCOUTFS_BTREE_GREATEST_KEY_LEN 32
-/* level >0 segments can have a full key and some metadata */
-#define SCOUTFS_BTREE_MAX_KEY_LEN 320
-/* level 0 segments can have two full keys in the value :/ */
-#define SCOUTFS_BTREE_MAX_VAL_LEN 768
+/* chose reasonable max key and value lens that have room for some u64s */
+#define SCOUTFS_BTREE_MAX_KEY_LEN 40
+#define SCOUTFS_BTREE_MAX_VAL_LEN 64
 
 /*
  * The min number of free bytes we must leave in a parent as we descend