diff --git a/btpd/main.c b/btpd/main.c
index d7bfc1e..6dd9bf3 100644
--- a/btpd/main.c
+++ b/btpd/main.c
@@ -111,7 +111,7 @@ usage(void)
         "\tListen at port n. Default is 6881.\n"
         "\n"
         "--prealloc n\n"
-        "\tPreallocate disk space in chunks of n kB. Default is 1.\n"
+        "\tPreallocate disk space in chunks of n kB. Default is 2048.\n"
         "\tNote that n will be rounded up to the closest multiple of the\n"
         "\ttorrent piece size. If n is zero no preallocation will be done.\n"
         "\n");
diff --git a/btpd/opts.c b/btpd/opts.c
index cccf2da..70f4925 100644
--- a/btpd/opts.c
+++ b/btpd/opts.c
@@ -11,4 +11,4 @@ unsigned net_max_peers;
 unsigned net_bw_limit_in;
 unsigned net_bw_limit_out;
 int net_port = 6881;
-off_t cm_alloc_size = 1;
+off_t cm_alloc_size = 2048;