diff --git a/src/bio/bio_xstream.c b/src/bio/bio_xstream.c
index d26a5f4bee1..74c058d3b55 100644
--- a/src/bio/bio_xstream.c
+++ b/src/bio/bio_xstream.c
@@ -1,5 +1,6 @@
 /**
  * (C) Copyright 2018-2024 Intel Corporation.
+ * (C) Copyright 2025 Hewlett Packard Enterprise Development LP
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -31,7 +32,7 @@
 /* SPDK blob parameters */
 #define DAOS_BS_CLUSTER_SZ	(1ULL << 25)	/* 32MB */
 /* DMA buffer parameters */
-#define DAOS_DMA_CHUNK_INIT_PCT	60	/* Default pre-xstream init chunks, in percentage */
+#define DAOS_DMA_CHUNK_INIT_PCT 50      /* Default per-xstream init chunks, in percentage */
 #define DAOS_DMA_CHUNK_CNT_MAX	128	/* Default per-xstream max chunks, 1GB */
 #define DAOS_DMA_CHUNK_CNT_MIN	32	/* Per-xstream min chunks, 256MB */
 
@@ -1686,7 +1687,9 @@ bio_xsctxt_alloc(struct bio_xs_context **pctxt, int tgt_id, bool self_polling)
 		D_ASSERT(d_bdev != NULL);
 	}
 
-	ctxt->bxc_dma_buf = dma_buffer_create(init_chk_cnt(), tgt_id);
+	/* Sys target only needs very limited DMA buffer for the WAL of RDB */
+	ctxt->bxc_dma_buf = dma_buffer_create(tgt_id == BIO_SYS_TGT_ID ? 1 : init_chk_cnt(),
+					      tgt_id);
 	if (ctxt->bxc_dma_buf == NULL) {
 		D_ERROR("failed to initialize dma buffer\n");
 		rc = -DER_NOMEM;