Re: Persitence Identifier

Keep in mind that using these server-initiated per-client cookie 
persistence methods means that the ADC needs to keep state information 
on each and every client until the cookie is allowed to expire. That can 
create a lot of overhead.

When the ADC issues a persistence cookie itself, it's usually encoded in 
a way that tells it which server to send the request to but it doesn't 
need to track every single cookie for every single client.


Surya ARBY wrote:
> Hello Tony.
>
> I guess the cookies generated on his apache services all have the same 
> name but all different values in the payload, so by using 
> cookie-learning the LB can recognize the right back end server to 
> forward the request, in fact this technique is perfectly similar to a 
> cookie insert where the payload of the cookie identifies the back end 
> service to use except that it's purely passive from the LB (if the 
> payload of the cookie generated by the apache is unique and stays 
> local). So to have this method working, the payload of cookies 
> generated must never be shared between two apache servers, in this 
> case persistance would be broken.
>
> Anand, using cookie insertion on the LB is a better method than cookie 
> learning because
>
> 1 - cookie learning consumes memory ressources (the LB has to build a 
> table where learnt values are stored), with cookie insertion some 
> vendors put in the payload the IP and the port of the back end service 
> used so the result of the persistance process is predictable and 
> deterministic (this is not the case with ALL vendors ok :) some also 
> use different cookie values and also build a table, Cisco ACE works 
> like that as I far as I know)
>
> 2 - the persistance cookie inserted is usually stripped off 
> automatically from the requests, it will not be the case with passive 
> cookie learning and some apps will break when receiving unexpected 
> cookies.
>
> regards,
>
> Surya
> *
> router# show problem | include solution*
>
>
> --- En date de : *Jeu 16.7.09, Tony Bourke /<[email protected]>/* a écrit :
>
>
>     De: Tony Bourke <[email protected]>
>     Objet: Re: [load balancing] Persitence Identifier
>     À: "Load Balancing Mailing List" <[email protected]>
>     Date: Jeudi 16 Juillet 2009, 18h24
>
>     Hello Anand,
>
>     Is there a particular reason you cannot use insert cookie mode?
>
>     Apache generally doesn't issue cookies, rather an application
>     platform like PHP or Tomacat would (running on top of Apache). 
>     The reason is that these application platforms will need to
>     generate a unique value for each user.  If you can get Apache to
>     generate a cookie, I'm not sure it would be unique.
>
>     If you do want to use passive cookie mode (where the web server
>     generates the cookie), the cookie value you generate will need to
>     be unique to each user.
>
>     The WSD 3000 should be capable (it's been a while since I've
>     logged into a Radware) of inserting its own cookie.  In your case,
>     that seems like it may be the best solution (I believe others have
>     already mentioned this).
>
>     Regards,
>
>     Tony
>
>
>
>
>
>     On Jul 16, 2009, at 7:37 AM, anand kumar wrote:
>
>     > Dear All,
>     >
>     > I have generated a cookie named "xyz " through my Apache Server
>     by giving Directives
>     > , but when i have connected the WSD 3000, i couldnt get the
>     cookie back,
>     > what i have to give in the cookie Key(Persistency identifier) on WSD
>     > --Anand.M
>     > HCL Infosystems Ltd
>     >
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