[cas-dev] high availability issue of CAS

[Scott Battaglia]

Most of our high-availability clustering shares information across
servers such that if one goes down the other can handle whatever the
downed server was doing.

-Scott

-Scott Battaglia
PGP Public Key Id: 0x383733AA
LinkedIn: http://www.linkedin.com/in/scottbattaglia



On Tue, Nov 18, 2008 at 10:14 PM, Lin George <george4academic at yahoo.com> wrote:
> Thanks Robert,
>
> I read your referred document, and it is really nice! But dues to my limited English skills, I still have one confusion which is 100% clear after I read it.
>
> Suppose we have two machines to make a cluster, say machine A and machine B, suppose user P's session information (stateful information CAS used) is stored in machine A, and machine B stores user Q's session information.
>
> If machine A is down, what will happen to user P? Must user P must enter again his/her credential and using machine B to authenticate? Or we could use the so-called cache replication approach to store P's credential information into machine Q?
>
> regards,
> George
>
> See http://www.ja-sig.org/wiki/display/CASUM/Clustering+CAS
>
> Robert
>
> Am 18.11.2008 um 13:35 schrieb Lin George:
>
>> Sorry for sending to multiple list because I am a new member and do
>> not know which list is better to send. It is appreciated if anyone
>> could advise me which list is the correct one to send this question.
>> I am a CAS new user not developer who wants to contribute CAS code
>> (I may contribute after I am familiar with CAS). :-)
>>
>> My question is, after reviewing CAS architecture, I have not found
>> how CAS ensures high availability and scalability.
>>
>> More specific question like this,
>>
>> - if I only setup one CAS authentication server (service), and if it
>> is not availabile for some reason (e.g. power-off), how to ensure
>> the whole authentication system (including web client and web
>> resources) still works? Or the whole system will not work -- i.e.
>> without authentication server (service), even if end user provides
>> valid credential, he/she can not access the web resources?
>>
>> - if the user base is large, how to setup multiple CAS
>> authentication servers (service) to balance load? I did not find
>> related information in the CAS wiki page.
>>
>> Any advice are welcome.
>>
>> thanks in advance,
>> George
>
>
>
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