diff --git a/src/builder/b-comms.c b/src/builder/b-comms.c
index 12c1af2..c027424 100644
--- a/src/builder/b-comms.c
+++ b/src/builder/b-comms.c
@@ -72,6 +72,39 @@ saib_m_tx(void *userobj, lws_ss_tx_ordinal_t ord, uint8_t *buf, size_t *len,
 	int n = 0;
 
 	/*
+	 * Any build metrics to process?
+	 */
+
+	if (spm->build_metric_list.count) {
+		struct lws_dll2 *d = lws_dll2_get_head(&spm->build_metric_list);
+		sai_build_metric_t *m =
+				lws_container_of(d, sai_build_metric_t, list);
+
+		lwsl_notice("%s: issuing build metric\n", __func__);
+
+		js = lws_struct_json_serialize_create(lsm_schema_build_metric,
+			      LWS_ARRAY_SIZE(lsm_schema_build_metric), 0, m);
+		if (!js)
+			return -1;
+
+		n = (int)lws_struct_json_serialize(js, start,
+					      lws_ptr_diff_size_t(end, start), &w);
+		lws_struct_json_serialize_destroy(&js);
+
+		lwsl_hexdump_notice(start, w);
+
+		n = (int)w;
+
+		lws_dll2_remove(&m->list);
+		free(m);
+
+		r = lws_ss_request_tx(spm->ss);
+		if (r)
+			return r;
+		goto sendify;
+	}
+
+	/*
 	 * Any builder state updates / rejections to process?
 	 */
 
diff --git a/src/builder/b-nspawn.c b/src/builder/b-nspawn.c
index 3b4d8d9..d262b24 100644
--- a/src/builder/b-nspawn.c
+++ b/src/builder/b-nspawn.c
@@ -244,11 +244,54 @@ sai_lsp_reap_cb(void *opaque, const lws_spawn_resource_us_t *res, siginfo_t *si,
 		saib_log_chunk_create(ns, s, (size_t)n, 3);
 	}
 
+	if (op->spawn) {
+		sai_build_metric_t *m = malloc(sizeof(*m));
+
+		if (m) {
+			char hash_input[8192];
+			unsigned char hash[32];
+			struct lws_genhash_ctx ctx;
+			int n;
+
+			memset(m, 0, sizeof(*m));
+
+			lws_snprintf(hash_input, sizeof(hash_input), "%s%s%s%s",
+				     ns->sp->name, op->spawn,
+				     ns->project_name, ns->ref);
+
+			if (lws_genhash_init(&ctx, LWS_GENHASH_TYPE_SHA256) ||
+			    lws_genhash_update(&ctx, hash_input,
+					       strlen(hash_input)) ||
+			    lws_genhash_destroy(&ctx, hash))
+				lwsl_warn("%s: sha256 failed\n", __func__);
+			else
+				for (n = 0; n < 32; n++)
+					lws_snprintf(m->key + (n * 2), 3,
+						     "%02x", hash[n]);
+
+			lws_strncpy(m->builder_name, ns->sp->name, sizeof(m->builder_name));
+			lws_strncpy(m->project_name, ns->project_name, sizeof(m->project_name));
+			lws_strncpy(m->ref, ns->ref, sizeof(m->ref));
+			m->parallel = ns->parallel;
+			m->us_cpu_user = res->us_cpu_user;
+			m->us_cpu_sys = res->us_cpu_sys;
+			m->wallclock_us = (uint64_t)(lws_now_usecs() - op->start_time);
+			m->peak_mem_rss = res->peak_mem_rss;
+			m->stg_bytes = du.size_in_bytes;
+
+			lws_dll2_add_tail(&m->list, &ns->spm->build_metric_list);
+			if (lws_ss_request_tx(ns->spm->ss))
+				lwsl_warn("%s: lws_ss_request_tx failed\n", __func__);
+		}
+	}
+
 	ns->build_step++;
 	if (ns->build_step < ns->build_step_count) {
 		/* there are more steps, spawn the next one */
 		if (ns)
 			ns->op = NULL;
+		if (op->spawn)
+			free(op->spawn);
 		free(op);
 		saib_spawn_step(ns);
 		return;
@@ -257,6 +300,9 @@ sai_lsp_reap_cb(void *opaque, const lws_spawn_resource_us_t *res, siginfo_t *si,
 	/* all steps succeeded */
 	lwsl_notice("%s: all build steps succeeded\n", __func__);
 
+	if (op->spawn)
+		free(op->spawn);
+
 	saib_task_grace(ns);
 	saib_set_ns_state(ns, NSSTATE_DONE);
 
@@ -286,6 +332,9 @@ fail:
 
 	saib_log_chunk_create(ns, NULL, 0, 2);
 
+	if (op->spawn)
+		free(op->spawn);
+
 	if (ns)
 		ns->op = NULL;
 	free(op);
@@ -515,6 +564,7 @@ saib_spawn_step(struct sai_nspawn *ns)
 	info.max_log_lines	= 10000;
 	info.timeout_us		= 30 * 60 * LWS_US_PER_SEC;
 	info.reap_cb		= sai_lsp_reap_cb;
+	memset(&ns->res, 0, sizeof(ns->res));
 	info.res		= &ns->res;
 #if defined(__linux__)
 	info.cgroup_name_suffix = cgroup;
@@ -528,6 +578,8 @@ saib_spawn_step(struct sai_nspawn *ns)
 
 	op->ns = ns;
 	ns->op = op;
+	op->spawn = strdup(one_step);
+	op->start_time = lws_now_usecs();
 
 	info.opaque = op;
 	info.owner = &builder.lsp_owner;
diff --git a/src/builder/b-private.h b/src/builder/b-private.h
index 6de26bf..264b9f0 100644
--- a/src/builder/b-private.h
+++ b/src/builder/b-private.h
@@ -42,6 +42,8 @@ struct lws_spawn_piped;
 struct saib_opaque_spawn {
 	struct sai_nspawn	*ns;
 	struct lws_spawn_piped	*lsp;
+	char			*spawn;
+	lws_usec_t		start_time;
 };
 
 #define SAI_LOAD_REPORT_US	(1 * LWS_US_PER_SEC)
diff --git a/src/common/include/private.h b/src/common/include/private.h
index 7997ad2..b4afe7e 100644
--- a/src/common/include/private.h
+++ b/src/common/include/private.h
@@ -363,6 +363,7 @@ typedef struct sai_plat_server {
 	lws_dll2_t		list;
 
 	lws_dll2_owner_t	rejection_list;
+	lws_dll2_owner_t	build_metric_list;
 	lws_dll2_owner_t	resource_req_list; /* sai_resource_msg_t */
 	lws_dll2_owner_t	resource_pss_list; /* so we can find the cookie */
 
@@ -483,6 +484,35 @@ typedef struct sai_power_state {
 	int		powering_down;
 } sai_power_state_t;
 
+typedef struct sai_build_metric {
+	lws_dll2_t	list;
+	char		key[65];
+	char		builder_name[96];
+	char		project_name[96];
+	char		ref[96];
+	int		parallel;
+	uint64_t	us_cpu_user;
+	uint64_t	us_cpu_sys;
+	uint64_t	wallclock_us;
+	uint64_t	peak_mem_rss;
+	uint64_t	stg_bytes;
+} sai_build_metric_t;
+
+typedef struct sai_build_metric_db {
+	lws_dll2_t	list; /* for lws_struct */
+	char		key[65];
+	uint64_t	unixtime;
+	char		builder_name[96];
+	char		project_name[96];
+	char		ref[96];
+	int		parallel;
+	uint64_t	us_cpu_user;
+	uint64_t	us_cpu_sys;
+	uint64_t	wallclock_us;
+	uint64_t	peak_mem_rss;
+	uint64_t	stg_bytes;
+} sai_build_metric_db_t;
+
 extern const lws_struct_map_t
 	lsm_schema_json_map_task[],
 	lsm_schema_sq3_map_task[],
@@ -506,8 +536,11 @@ extern const lws_struct_map_t
 	lsm_resource[4],
 	lsm_power_state[3],
 	lsm_rebuild[1],
-	lsm_schema_rebuild[1]
+	lsm_schema_rebuild[1],
+	lsm_schema_build_metric[1],
+	lsm_schema_sq3_map_build_metric[1]
 ;
+extern const lws_struct_map_t lsm_build_metric[10];
 extern const lws_struct_map_t lsm_plat[8];
 extern const lws_struct_map_t lsm_plat_for_json[12];
 
diff --git a/src/common/struct-metadata.c b/src/common/struct-metadata.c
index 58c8dc5..21caec9 100644
--- a/src/common/struct-metadata.c
+++ b/src/common/struct-metadata.c
@@ -40,6 +40,41 @@ const lws_struct_map_t lsm_load_report_members[] = {
 			 NULL, lsm_platform_load, "platforms"),
 };
 
+const lws_struct_map_t lsm_build_metric[] = {
+	LSM_CARRAY	(sai_build_metric_t, key,		"key"),
+	LSM_CARRAY	(sai_build_metric_t, builder_name,	"builder_name"),
+	LSM_CARRAY	(sai_build_metric_t, project_name,	"project_name"),
+	LSM_CARRAY	(sai_build_metric_t, ref,		"ref"),
+	LSM_SIGNED	(sai_build_metric_t, parallel,		"parallel"),
+	LSM_UNSIGNED	(sai_build_metric_t, us_cpu_user,	"us_cpu_user"),
+	LSM_UNSIGNED	(sai_build_metric_t, us_cpu_sys,	"us_cpu_sys"),
+	LSM_UNSIGNED	(sai_build_metric_t, wallclock_us,	"wallclock_us"),
+	LSM_UNSIGNED	(sai_build_metric_t, peak_mem_rss,	"peak_mem_rss"),
+	LSM_UNSIGNED	(sai_build_metric_t, stg_bytes,		"stg_bytes"),
+};
+
+const lws_struct_map_t lsm_schema_build_metric[] = {
+	LSM_SCHEMA	(sai_build_metric_t, NULL, lsm_build_metric, "com.warmcat.sai.build-metric")
+};
+
+const lws_struct_map_t lsm_sq3_build_metric[] = {
+	LSM_CARRAY	(sai_build_metric_db_t, key,		"key"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, unixtime,	"unixtime"),
+	LSM_CARRAY	(sai_build_metric_db_t, builder_name,	"builder_name"),
+	LSM_CARRAY	(sai_build_metric_db_t, project_name,	"project_name"),
+	LSM_CARRAY	(sai_build_metric_db_t, ref,		"ref"),
+	LSM_SIGNED	(sai_build_metric_db_t, parallel,	"parallel"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, us_cpu_user,	"us_cpu_user"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, us_cpu_sys,	"us_cpu_sys"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, wallclock_us,	"wallclock_us"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, peak_mem_rss,	"peak_mem_rss"),
+	LSM_UNSIGNED	(sai_build_metric_db_t, stg_bytes,	"stg_bytes"),
+};
+
+const lws_struct_map_t lsm_schema_sq3_map_build_metric[] = {
+	LSM_SCHEMA_DLL2	(sai_build_metric_db_t, list, NULL, lsm_sq3_build_metric, "build_metrics"),
+};
+
 const lws_struct_map_t lsm_plat[] = { /* !!! keep extern length in common/include/private.h in sync */
 	LSM_UNSIGNED	(sai_plat_t, uid,		"uid"),
 	LSM_STRING_PTR	(sai_plat_t, name,		"name"),
diff --git a/src/server/CMakeLists.txt b/src/server/CMakeLists.txt
index 9b5eaba..774e0f7 100644
--- a/src/server/CMakeLists.txt
+++ b/src/server/CMakeLists.txt
@@ -12,6 +12,7 @@ set(SRCS
 	s-central.c
 	s-websrv.c
 	s-resource.c
+	s-metrics-db.c
 	../common/c-utils.c
 )
 
diff --git a/src/server/s-metrics-db.c b/src/server/s-metrics-db.c
new file mode 100644
index 0000000..685c32e
--- /dev/null
+++ b/src/server/s-metrics-db.c
@@ -0,0 +1,163 @@
+/*
+ * Sai server metrics db
+ *
+ * Copyright (C) 2024 Andy Green <andy@warmcat.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation:
+ *  version 2.1 of the License.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *  MA  02110-1301  USA
+ */
+
+#include <libwebsockets.h>
+
+#include "s-private.h"
+#include "s-metrics-db.h"
+
+static int
+sais_metrics_db_prune(struct vhd *vhd, const char *key)
+{
+	sqlite3_stmt *stmt;
+	char sql[256];
+	int rc, count = 0;
+
+	if (!vhd->pdb_metrics)
+		return 0;
+
+	lws_snprintf(sql, sizeof(sql),
+		     "SELECT COUNT(*) FROM build_metrics WHERE key = ?;");
+
+	rc = sqlite3_prepare_v2(vhd->pdb_metrics, sql, -1, &stmt, 0);
+	if (rc != SQLITE_OK) {
+		lwsl_err("%s: failed to prepare statement: %s\n", __func__,
+			 sqlite3_errmsg(vhd->pdb_metrics));
+		return 1;
+	}
+
+	sqlite3_bind_text(stmt, 1, key, -1, SQLITE_STATIC);
+
+	if (sqlite3_step(stmt) == SQLITE_ROW)
+		count = sqlite3_column_int(stmt, 0);
+
+	sqlite3_finalize(stmt);
+
+	if (count <= 10)
+		return 0;
+
+	lws_snprintf(sql, sizeof(sql),
+		     "DELETE FROM build_metrics WHERE key = ? AND rowid IN "
+		     "(SELECT rowid FROM build_metrics WHERE key = ? "
+		     "ORDER BY unixtime ASC LIMIT %d);", count - 10);
+
+	rc = sqlite3_prepare_v2(vhd->pdb_metrics, sql, -1, &stmt, 0);
+	if (rc != SQLITE_OK) {
+		lwsl_err("%s: failed to prepare statement: %s\n", __func__,
+			 sqlite3_errmsg(vhd->pdb_metrics));
+		return 1;
+	}
+
+	sqlite3_bind_text(stmt, 1, key, -1, SQLITE_STATIC);
+	sqlite3_bind_text(stmt, 2, key, -1, SQLITE_STATIC);
+
+	rc = sqlite3_step(stmt);
+	if (rc != SQLITE_DONE) {
+		lwsl_err("%s: failed to delete old metrics: %s\n", __func__,
+			 sqlite3_errmsg(vhd->pdb_metrics));
+		sqlite3_finalize(stmt);
+		return 1;
+	}
+
+	sqlite3_finalize(stmt);
+
+	return 0;
+}
+
+int
+sais_metrics_db_init(struct vhd *vhd)
+{
+	char db_path[PATH_MAX];
+	int rc;
+
+	if (vhd->pdb_metrics)
+		return 0;
+
+	if (!vhd->sqlite3_path_lhs)
+		return 0;
+
+	lws_snprintf(db_path, sizeof(db_path), "%s-build-metrics.sqlite3",
+		     vhd->sqlite3_path_lhs);
+
+	rc = sqlite3_open(db_path, &vhd->pdb_metrics);
+	if (rc != SQLITE_OK) {
+		lwsl_err("%s: cannot open database %s: %s\n", __func__,
+			 db_path, sqlite3_errmsg(vhd->pdb_metrics));
+		sqlite3_close(vhd->pdb_metrics);
+		vhd->pdb_metrics = NULL;
+		return 1;
+	}
+
+	if (lws_struct_sq3_create_table(vhd->pdb_metrics,
+					lsm_schema_sq3_map_build_metric)) {
+		lwsl_err("%s: failed to create build_metrics table\n", __func__);
+		sqlite3_close(vhd->pdb_metrics);
+		vhd->pdb_metrics = NULL;
+		return 1;
+	}
+
+	return 0;
+}
+
+void
+sais_metrics_db_close(void)
+{
+	/* This is managed by the vhd destruction */
+}
+
+int
+sais_metrics_db_add(struct vhd *vhd, const struct sai_build_metric *m)
+{
+	sai_build_metric_db_t dbm;
+	lws_dll2_owner_t owner;
+
+	if (!vhd->pdb_metrics)
+		return 0;
+
+	memset(&dbm, 0, sizeof(dbm));
+
+	lws_strncpy(dbm.key, m->key, sizeof(dbm.key));
+	dbm.unixtime = (uint64_t)time(NULL);
+	lws_strncpy(dbm.builder_name, m->builder_name, sizeof(dbm.builder_name));
+	lws_strncpy(dbm.project_name, m->project_name, sizeof(dbm.project_name));
+	lws_strncpy(dbm.ref, m->ref, sizeof(dbm.ref));
+	dbm.parallel = m->parallel;
+	dbm.us_cpu_user = m->us_cpu_user;
+	dbm.us_cpu_sys = m->us_cpu_sys;
+	dbm.wallclock_us = m->wallclock_us;
+	dbm.peak_mem_rss = m->peak_mem_rss;
+	dbm.stg_bytes = m->stg_bytes;
+
+	lws_dll2_owner_clear(&owner);
+	lws_dll2_add_tail(&dbm.list, &owner);
+
+	if (lws_struct_sq3_serialize(vhd->pdb_metrics,
+				     lsm_schema_sq3_map_build_metric,
+				     &owner, 0)) {
+		lwsl_err("%s: failed to serialize build metric\n", __func__);
+		return 1;
+	}
+
+	if (sais_metrics_db_prune(vhd, dbm.key))
+		lwsl_warn("%s: pruning metrics failed\n", __func__);
+
+	return 0;
+}
diff --git a/src/server/s-metrics-db.h b/src/server/s-metrics-db.h
new file mode 100644
index 0000000..d7f8093
--- /dev/null
+++ b/src/server/s-metrics-db.h
@@ -0,0 +1,37 @@
+/*
+ * Sai server metrics db
+ *
+ * Copyright (C) 2024 Andy Green <andy@warmcat.com>
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation:
+ *  version 2.1 of the License.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *  MA  02110-1301  USA
+ */
+
+#if !defined(__SAI_SERVER_METRICS_DB_H__)
+#define __SAI_SERVER_METRICS_DB_H__
+
+struct vhd;
+struct sai_build_metric;
+
+int
+sais_metrics_db_init(struct vhd *vhd);
+
+void
+sais_metrics_db_close(void);
+
+int
+sais_metrics_db_add(struct vhd *vhd, const struct sai_build_metric *m);
+
+#endif
diff --git a/src/server/s-private.h b/src/server/s-private.h
index d73368e..714bbb1 100644
--- a/src/server/s-private.h
+++ b/src/server/s-private.h
@@ -210,6 +210,7 @@ struct vhd {
 	struct lwsac			*ac_plats;
 
 	const char *sqlite3_path_lhs;
+	sqlite3 *pdb_metrics;
 
 	lws_dll2_owner_t sqlite3_cache; /* sais_sqlite_cache_t */
 	lws_dll2_owner_t tasklog_cache;
diff --git a/src/server/s-ws-builder.c b/src/server/s-ws-builder.c
index 29deb0e..1aa7411 100644
--- a/src/server/s-ws-builder.c
+++ b/src/server/s-ws-builder.c
@@ -28,6 +28,7 @@
 #include <time.h>
 
 #include "s-private.h"
+#include "s-metrics-db.h"
 
 typedef struct {
 	int count;
@@ -95,6 +96,8 @@ static const lws_struct_map_t lsm_schema_map_ba[] = {
 						"com.warmcat.sai.loadreport"),
 	LSM_SCHEMA      (sai_resource_t,  NULL, lsm_resource,
 						"com-warmcat-sai-resource"),
+	LSM_SCHEMA	(sai_build_metric_t, NULL, lsm_build_metric,
+						"com.warmcat.sai.build-metric"),
 };
 
 enum {
@@ -104,6 +107,7 @@ enum {
 	SAIM_WSSCH_BUILDER_ARTIFACT,
 	SAIM_WSSCH_BUILDER_LOADREPORT,
 	SAIM_WSSCH_BUILDER_RESOURCE_REQ,
+	SAIM_WSSCH_BUILDER_METRIC,
 };
 
 static void
@@ -484,6 +488,7 @@ int
 sais_ws_json_rx_builder(struct vhd *vhd, struct pss *pss, uint8_t *buf, size_t bl)
 {
 	char event_uuid[33], s[128], esc[96];
+	const sai_build_metric_t *metric;
 	sai_resource_requisition_t *rr;
 	sai_resource_wellknown_t *wk;
 	struct lwsac *ac = NULL;
@@ -497,6 +502,8 @@ sais_ws_json_rx_builder(struct vhd *vhd, struct pss *pss, uint8_t *buf, size_t b
 	uint64_t rid;
 	int n, m;
 
+	sais_metrics_db_init(vhd);
+
 	if (pss->bulk_binary_data) {
 		lwsl_info("%s: bulk %d\n", __func__, (int)bl);
 		m = (int)bl;
@@ -1044,6 +1051,11 @@ bail:
 		sais_resource_check_if_can_accept_queued(wk);
 		break;
 
+	case SAIM_WSSCH_BUILDER_METRIC:
+		metric = (const sai_build_metric_t *)pss->a.dest;
+		sais_metrics_db_add(vhd, metric);
+		lwsac_free(&pss->a.ac);
+		break;
 	}
 
 	return 0;