DNS cache and memory usage, without adlist

Another “proof” that memory is likely to get allocated beyond the allowed limit.

Cache used is 270000 KiB which is the configured max. I raise the limit to 500000 KiB. In a second (4 seconds between my commands actually) I have 356xxx KiB used. That’s almost 100 MB increase instantly. This is because I have waited ~2 days with raising the limit.

Right now it seems like I will have to reboot the router every second month or so to make sure that it has memory enough.

[admin@router-01] /ip/dns> /system/clock/print ; /ip/dns/print ; /ip/dns/cache print count-only
                  time: 09:26:11        
                  date: 2025-04-13      
  time-zone-autodetect: yes             
        time-zone-name: Europe/Stockholm
            gmt-offset: +02:00          
            dst-active: yes             
                      servers: 1.1.1.1  
                               8.8.8.8  
                               1.0.0.1  
                               8.8.4.4  
              dynamic-servers:          
               use-doh-server:          
              verify-doh-cert: no       
   doh-max-server-connections: 5        
   doh-max-concurrent-queries: 50       
                  doh-timeout: 5s       
        allow-remote-requests: yes      
          max-udp-packet-size: 1024     
         query-server-timeout: 2s       
          query-total-timeout: 10s      
       max-concurrent-queries: 500      
  max-concurrent-tcp-sessions: 20       
                   cache-size: 270000KiB
                cache-max-ttl: 1h       
      address-list-extra-time: 0s       
                          vrf: main     
           mdns-repeat-ifaces: vlan1604 
                               vlan1605 
                   cache-used: 270000KiB
868
[admin@router-01] /ip/dns> /ip/dns/set cache-size=500000KiB
[admin@router-01] /ip/dns> /system/clock/print ; /ip/dns/print ; /ip/dns/cache print count-only
                  time: 09:26:15        
                  date: 2025-04-13      
  time-zone-autodetect: yes             
        time-zone-name: Europe/Stockholm
            gmt-offset: +02:00          
            dst-active: yes             
                      servers: 1.1.1.1  
                               8.8.8.8  
                               1.0.0.1  
                               8.8.4.4  
              dynamic-servers:          
               use-doh-server:          
              verify-doh-cert: no       
   doh-max-server-connections: 5        
   doh-max-concurrent-queries: 50       
                  doh-timeout: 5s       
        allow-remote-requests: yes      
          max-udp-packet-size: 1024     
         query-server-timeout: 2s       
          query-total-timeout: 10s      
       max-concurrent-queries: 500      
  max-concurrent-tcp-sessions: 20       
                   cache-size: 500000KiB
                cache-max-ttl: 1h       
      address-list-extra-time: 0s       
                          vrf: main     
           mdns-repeat-ifaces: vlan1604 
                               vlan1605 
                   cache-used: 356223KiB
904