diff --git a/backend/src/controllers/adminController.js b/backend/src/controllers/adminController.js
index 9c6ce00..76a235f 100644
--- a/backend/src/controllers/adminController.js
+++ b/backend/src/controllers/adminController.js
@@ -648,6 +648,21 @@ function _dbTables() {
   } catch { return []; }
 }
 
+// Активные проверки: отклик БД (мс) и тест записи на диск рядом с БД.
+function _runChecks() {
+  let dbPingMs = null, dbOk = false;
+  try { const t = process.hrtime.bigint(); db.prepare('SELECT 1 AS ok').get(); dbPingMs = Number(process.hrtime.bigint() - t) / 1e6; dbOk = true; } catch {}
+  let diskWritable = false;
+  try {
+    const f = path.join(path.dirname(path.resolve(DB_PATH)), '.health-write-test');
+    fs.writeFileSync(f, 'ok'); fs.unlinkSync(f); diskWritable = true;
+  } catch {}
+  return { dbPingMs, dbOk, diskWritable };
+}
+const _recentErrStmt = db.prepare(
+  "SELECT id, level, message, route, method, created_at FROM error_log ORDER BY id DESC LIMIT 8"
+);
+
 function getHealth(_req, res) {
   const uptimeSec = process.uptime();
   const mem = process.memoryUsage();
@@ -672,6 +687,10 @@ function getHealth(_req, res) {
   let sseStats = { users: 0, guests: 0, connections: 0 };
   try { sseStats = sse.stats(); } catch {}
 
+  // Активные health-проверки (Level 4): отклик БД и запись на диск.
+  const checks = _runChecks();
+  const recentErrorList = (() => { try { return _recentErrStmt.all(); } catch { return []; } })();
+
   // Вердикт здоровья по порогам.
   const reasons = [];
   let status = 'ok';
@@ -688,9 +707,13 @@ function getHealth(_req, res) {
   if (eventLoopLagMs > 200)      crit(`Лаг event-loop ${eventLoopLagMs.toFixed(0)} мс`);
   else if (eventLoopLagMs > 70)  warn(`Лаг event-loop ${eventLoopLagMs.toFixed(0)} мс`);
   if (dbSizeBytes > 1.5e9) warn('БД >1.5 ГБ');
+  if (!checks.dbOk)        crit('БД недоступна');
+  if (!checks.diskWritable) crit('Диск недоступен для записи');
+  if (checks.dbPingMs != null && checks.dbPingMs > 100) warn(`Медленный отклик БД ${checks.dbPingMs.toFixed(0)} мс`);
 
   res.json({
     status, reasons,
+    checks, recentErrorList,
     uptime: uptimeSec,
     startedAt: new Date(Date.now() - uptimeSec * 1000).toISOString(),
     memory: { rss: mem.rss, heapUsed: mem.heapUsed, heapTotal: mem.heapTotal },
diff --git a/frontend/js/admin/admin.js b/frontend/js/admin/admin.js
index b024712..830485c 100644
--- a/frontend/js/admin/admin.js
+++ b/frontend/js/admin/admin.js
@@ -388,6 +388,30 @@
         </div></div>`;
     }
 
+    // ── панель диагностики (Level 4): health-чеки + последние ошибки ──
+    let diagHtml = '';
+    {
+      const ch = h.checks || {};
+      const okCol = '#4ade80', badCol = 'var(--pink)';
+      const chip = (label, ok, extra) => `<div style="display:flex;align-items:center;gap:6px;font-size:.82rem"><span style="width:9px;height:9px;border-radius:50%;background:${ok?okCol:badCol}"></span>${label}${extra?` <span style="color:var(--text-3)">${extra}</span>`:''}</div>`;
+      const errs = h.recentErrorList || [];
+      const lvlCol = l => l==='error'||l==='fatal'?'var(--pink)':l==='warn'?'#facc15':'var(--text-3)';
+      diagHtml = `<div class="adm-panel" style="margin:14px 0 0">
+        <div class="adm-panel-title">Диагностика</div>
+        <div style="display:flex;gap:20px;flex-wrap:wrap;margin:6px 0 14px">
+          ${chip('База данных', !!ch.dbOk, ch.dbPingMs!=null?ch.dbPingMs.toFixed(2)+' мс':'')}
+          ${chip('Запись на диск', !!ch.diskWritable, ch.diskWritable?'доступна':'НЕДОСТУПНА')}
+        </div>
+        <div style="font-size:.72rem;color:var(--text-3);font-weight:700;text-transform:uppercase;margin-bottom:5px">Последние ошибки</div>
+        ${errs.length ? errs.map(e=>`<div style="display:flex;align-items:baseline;gap:8px;font-size:.78rem;padding:3px 0;border-bottom:1px solid rgba(255,255,255,.04)">
+            <span style="color:var(--text-3);white-space:nowrap;font-size:.72rem">${esc((e.created_at||'').replace('T',' ').slice(5,16))}</span>
+            <span style="color:${lvlCol(e.level)};font-weight:700;white-space:nowrap">${esc(e.level||'')}</span>
+            ${e.route?`<span style="color:var(--text-3);white-space:nowrap">${esc(e.method||'')} ${esc(e.route)}</span>`:''}
+            <span style="flex:1;color:var(--text-2);overflow:hidden;text-overflow:ellipsis;white-space:nowrap">${esc(e.message||'')}</span>
+          </div>`).join('') : `<div style="color:var(--green);font-size:.82rem">Ошибок нет</div>`}
+      </div>`;
+    }
+
     el.innerHTML = `
       <div class="adm-panel" style="margin:0 0 16px;padding:14px 18px;display:flex;align-items:center;gap:14px;border-left:4px solid ${stColor}">
         <div style="width:13px;height:13px;border-radius:50%;background:${stColor};box-shadow:0 0 12px ${stColor};flex-shrink:0"></div>
@@ -440,6 +464,8 @@
 
       ${trendsHtml}
 
+      ${diagHtml}
+
       <div class="adm-panel" style="margin:14px 0 0">
         <div class="adm-panel-title">Крупнейшие таблицы БД</div>
         ${(h.db.tables||[]).map(t=>`<div style="display:flex;align-items:center;gap:10px;margin:4px 0">