Updated FAQ (markdown)

FAQ.md

@@ -2139,5 +2139,43 @@ This would be important so the remote party can point things out during a sessio
 <img width="622" height="800" alt="b7586939-9513-40b8-8609-a6fb1d666725" src="https://github.com/user-attachments/assets/bb07d01c-7b0a-4e0a-a447-3be915315d13" />
 
 
+## Too many open files (os error 24)
 
+the hbbs process has reached its open-file descriptor limit.
+
+For a Docker Compose installation, increase the nofile limit for both hbbs and hbbr:
+
+```
+services:
+  hbbs:
+    ulimits:
+      nofile:
+        soft: 1000000
+        hard: 1000000
+
+  hbbr:
+    ulimits:
+      nofile:
+        soft: 1000000
+        hard: 1000000
+```
+
+After modifying `compose.yml`, recreate the containers. A normal restart does not apply the new ulimits settings:
+
+cd /path/to/compose.yml/directory
+
+`docker compose down`
+`docker compose up -d`
+
+You can verify the new limit with:
+```
+HBBS_CONTAINER=hbbs
+
+docker exec "$HBBS_CONTAINER" sh -c '
+HBBS_PID=$(pidof hbbs)
+grep -i "open files" /proc/$HBBS_PID/limits
+'
+```
+
+Replace hbbs with the actual container name if necessary.