diff --git a/sys/fs/nfs/nfsproto.h b/sys/fs/nfs/nfsproto.h
index 6e67c5be341..1054c85d8e8 100644
--- a/sys/fs/nfs/nfsproto.h
+++ b/sys/fs/nfs/nfsproto.h
@@ -89,8 +89,11 @@
  * It used to be called NFS_MAXDATA, but has been renamed to clarify that
  * it refers to server side only and doesn't conflict with the NFS_MAXDATA
  * defined in rpcsvc/nfs_prot.h for userland.
+ * NFS_SRVMAXIO is the default setting for vfs.nfsd.srvmaxio
+ * NFS_SRVLIMITIO is the maximum setting allowed for vfs.nfsd.srvmaxio
  */
 #define	NFS_SRVMAXIO	(128 * 1024)
+#define	NFS_SRVLIMITIO	(4 * 1024 * 1024)
 
 /* Stat numbers for rpc returns (version 2, 3 and 4) */
 /*
diff --git a/sys/fs/nfsserver/nfs_nfsdport.c b/sys/fs/nfsserver/nfs_nfsdport.c
index e42d5ca1e0a..1e6936ed351 100644
--- a/sys/fs/nfsserver/nfs_nfsdport.c
+++ b/sys/fs/nfsserver/nfs_nfsdport.c
@@ -241,8 +241,9 @@ sysctl_srvmaxio(SYSCTL_HANDLER_ARGS)
 		printf("nfsd: vfs.nfsd.srvmaxio can only be increased\n");
 		return (EINVAL);
 	}
-	if (newsrvmaxio > 1048576) {
-		printf("nfsd: vfs.nfsd.srvmaxio cannot be > 1Mbyte\n");
+	if (newsrvmaxio > NFS_SRVLIMITIO) {
+		printf("nfsd: vfs.nfsd.srvmaxio cannot be > %d\n",
+		    NFS_SRVLIMITIO);
 		return (EINVAL);
 	}
 	if ((newsrvmaxio & (newsrvmaxio - 1)) != 0) {