diff --git a/lib/nvmf/ctrlr.c b/lib/nvmf/ctrlr.c
index 9b0f6ae73..2f23b2f78 100644
--- a/lib/nvmf/ctrlr.c
+++ b/lib/nvmf/ctrlr.c
@@ -2650,7 +2650,7 @@ spdk_nvmf_ctrlr_identify_ctrlr(struct spdk_nvmf_ctrlr *ctrlr, struct spdk_nvme_c
 	cdata->maxcmd = transport->opts.max_queue_depth;
 	cdata->sgls = ctrlr->cdata.sgls;
 	cdata->fuses.compare_and_write = 1;
-	cdata->acwu = 1;
+	cdata->acwu = 0; /* ACWU is 0-based. */
 	if (subsystem->flags.ana_reporting) {
 		cdata->mnan = subsystem->max_nsid;
 	}