Kernel Tables Calculation

[Petrus_Rossouw]

Is there a calculation tool available for the kernel table sizes. I might have to increase the size of the hold_table on one of my firewall clusters and would like to calculate the optimal size for the available memory and current usage thereof.

[G_W_Albrecht]

While adjusting the hold timer is possible, it is strongly not recommended - see the sk44711 Kernel debug shows that TCP traffic is "dropped by fwhold_expires Reason: held chain expired" for detailed explanations. The hold table change ic covered in sk107324 Some traffic does not pass through Security Gateway and kernel debug shows "...dropped by fw_filter_chain Reason: chain hold".

There is no calculation for the optimal size - you have to raise it slowly until the drops disappear. Memory consumtion will grow of course...

[G_W_Albrecht · Accepted solution]

I would strongly suggest to involve TAC instead of blundering ...

[_Val_]

second that

[Petrus_Rossouw]

Thank you for the feedback. I was never going to blunder through this and would certainly first check with Tac. I was however hoping to do a calculation of how much memory would increase by if I up the table by 25 or 50. The box have a fairly large memory reserve.