--- mdadm-4.1/mdadm.c~ 2018-12-12 17:15:41.359619760 +0800 +++ mdadm-4.1/mdadm.c 2018-12-12 17:16:09.265626436 +0800 @@ -1553,6 +1553,10 @@ c.delay = DEFAULT_BITMAP_DELAY; if (c.nodes) { + pr_err("WARNING: bitmap=clustered is Technology Preview.\n"); + pr_err("For more information on Technology Preview features, visit:\n"); + pr_err("https://access.redhat.com/support/offerings/techpreview/ \n"); + if (!s.bitmap_file || strcmp(s.bitmap_file, "clustered") != 0) { pr_err("--nodes argument only compatible with --bitmap=clustered\n");