Hello,
We have a Mikrotik CCR 1072 and some days ago we had some ddos attack then we announce the attacked prefixes towards our ddos protected IP transits but after time about 1-2 days later we cpu our cpu usages are about %40-45 and our memory normally is 15g but its 14g then we found out that the issue is with IP route cache , when i disable that my cpu usages back to under %6-8 and memory back to 15g so:
1) if i keep route cache disabled do i face any issue? i just disable connection tracking and i have some bgp and clans and routing protocols, so disabling route cache does not cause any issue?
2) do you have any idea how to fix this by enable IP route cache?
Thanks,

Hello,
We have a Mikrotik CCR 1072 and some days ago we had some ddos attack then we announce the attacked prefixes towards our ddos protected IP transits but after time about 1-2 days later we cpu our cpu usages are about %40-45 and our memory normally is 15g but its 14g then we found out that the issue is with IP route cache , when i disable that my cpu usages back to under %6-8 and memory back to 15g so:
1) if i keep route cache disabled do i face any issue? i just disable connection tracking and i have some bgp and clans and routing protocols, so disabling route cache does not cause any issue?
2) do you have any idea how to fix this by enable IP route cache?
Thanks,

Do you use fastpath or fast track? Apparently they won't run with route cache turned off.
However I'm not actually 100% sure if that's actually the case for bridges, MPLS etc.

We have had the route cache turned off for years now, we use MPLS, OSPF and BGP.
Performance issues, we haven't noticed any difference with it turned off.

so if it will be off you think there is no performance issue or performance degree ?
because honestly sometimes route cache bother me too much due to high cpu usages and when i turn it off my cpu usages will degree from %50 to under %8

route cache has been removed from newer linux kernels because of the performance impact under load.
Turn route cache off, your router will survive a bit better in a DDoS with it disabled.