[RADIATOR] Rejection when server is overloaded

[C R]

Hi Stefan,

The experience I had in the past was that an the kernel of an
overloaded Linux server will drop UTP packages before Radiator has any
chance to see them. This happened when a CPU reached +80% cpu usage.
In order to be able to scale horizontally, I think RADIUS proxying is
the way to go (HW like Netscaler or a Radiator on front doing async
requests),

Regards,

C.

Le mar. 22 mars 2022 à 23:45, Stefan Paetow <Stefan.Paetow at jisc.ac.uk> a écrit :
>
> Hi,
>
>
>
> We’ve run across an odd problem. One of our members has staff who visit a variety of other eduroam organisations in the area, and yet there are some where it is categorically impossible for them to log in. When I browsed our logs, we would see an Access-Accept for their login, followed 9 or so seconds later by an Access-Reject. When we did a tcpdump, we found that the Access-Reject simply was a ‘Request denied’. Is there a way to see why this occurs? We’ve run our server in debug mode for a very short period, and then trimmed the debug log to the approximate period for the messages, and will be happy to provide those bits, but I’m wondering whether Radiator, when it is overloaded, simply ignores the packets that keep coming or rejects them with a ‘Request denied’? If it’s the latter, can that message be customized to see that this is indeed the case? I’ve added a RejectHasReason to all the realm handlers on the server to at least see when there is a problem that way.
>
>
>
> Before you ask, we’re already running with an almost maximum queue, on a 32 core processor and 64 threads (two per core) in order to provide enough threads that can do ‘stuff’. I can only assume this is the right way of dealing with overloading, i.e. provide more threads?
>
>
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> Any help is very much appreciated.
>
>
>
> With kind regards
>
>
>
> Stefan Paetow
> Federated Roaming Technical Specialist
>
>
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