Advise on enterprize application + clustering

K nnoydb at
Wed Aug 4 15:34:55 EDT 2004

If one could replace the stdin and stout handles with sockets a fork could be executed for redundcy a pipe proxy can be created for the remote process (created via sshd ir what ever sheel system you wish to use).

I have been conversing with RR developers about this topic.



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Any resemblance between the above and my own views is non-deterministic.

 The question of the existence of views in the absence of anyone to hold
is left as an exercise for the reader. The question of the existence of
the reader
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scope of this article.)

 --- On Wed 08/04, Pierre Sahores < psahores at > wrote:
From: Pierre Sahores [mailto: psahores at]
To: x at, use-revolution at
Date: Wed, 4 Aug 2004 18:42:38 +0200
Subject: Re: Advise on enterprize application + clustering

Grettings, All,<br><br>Le 3 août 04, à 08:01, MisterX a écrit :<br><br>> This is getting interesting... A bit of everything to solve<br>> your problem (x's famous howitzer approach). The last part<br>> may be even more interesting than the first. Remember that<br>> enterprise means also redundancy and zero-downtime ;)<br><br>!!! --> Always have this in mind (aka : only ACID compliant RDBMS <br>back-ends are eligibles there). In respecting this basis, the <br>applications server will always be cleanly designed (with, sorry for <br>the possibles Java's addicts reading us, to the end, Tomcat, JBoss no <br>more suitables at all than Metacard or Revolution...).<br><br><br>> Unfortunately there is some risks of lock ups if not done<br>> carefully... But here are 3 things you could try:<br>><br>> 1)<br>><br>> In a three tiered cluster strategy, mentioned in a clustering<br>> class I had recently, there were three actors<br>><br>>   client -> server1 -> server2<br>><br>>   client -> server2 is not possible because of the firewall.<br>><br>>   but server1 -> server2 is fine and client -> server1 is ok2<br><br>An usefull ports translation strategy, always very suitable, even in <br>about proxying / firewalling applications servers...<br>><br>>   if client cannot use sql but can use client1's ports,<br>>   and assuming client1 and client2 can do the sql bit...<br>><br>>   then you need a port configurable client server networking<br>>   protocol.<br>><br>>   in brief:<br>>   RRclient -> RR on Server -> SQLserver<br>><br>>   between RRclient and RRserver you use whatever protocol (80!)<br>>   Best is to have your client ask their network administrator<br>>   to see what is allowed and for what purpose.<br>><br>>   If you saw the forms we have to fill in for these requests<br>>   at my office you would scream!<br><br>For sure very cool and secure from the cluster administrator's point of <br>view...<br>><br>> 2)<br>><br>> For the clustering part now... For a redundant server...<br>>   but you can have more than one server also...<br>><br>>   Run two instances of RR. Named RRServer1 and RRS2.<br>>   Now only one application must work with the port communication<br>>   at the time but you can imagine either that one is locked up,<br>>   not responding, or working hard. It would be nice to have RR2<br>>   take over the next client's server call...<br>><br>>   What you do, is create a temporary file called rr1alive where<br>>   you write a frequent log - the frequency is the timeout for RR2<br>>   to kick and start working.<br>><br>>   There's the case where the RR1alive file is locked by the RR1,<br>>   which should be working but which should be closing the file.<br>><br>>   (is there a FileLocked(filepath) function in rr?)<br>>   You can use the file's date from the extended files function to<br>>   see the date anyway.<br>><br>>   So if there is a timeout trying to read that file, RR1 must be<br>>   locked. Terminate the process RR1. Relaunch RR1 and give it the<br>>   hand when you finished the current client processing.<br>><br>>   Note: usage of a different log for operations than the alivelog<br>>   is worth the trouble. You could keep a log opened in the case of<br>>   a processing but the alivelog should be kept closed to see when<br>>   the last alive was logged to prevent a double server taking parts<br>>   each of the same client's transactions (this can be prevented ez).<br>><br>>   Since transactions with SQL could take a while and queue up clients<br>>   you could imagine that another RRx takes over while the other<br>>   apps finish their transactions.<br><br>Hum ! I like your proposal design, Xavier but why would we have to <br>reinvent the wheel of the "transactions manager concept" when we can <br>let Apache (on the in/out to public/VPN internet side) and the ACID-DB <br>transactions managers handle tthat all for our Rev's applications <br>server ?<br>><br>> 3)<br>>   The cherry on the cake<br>><br>>   Now, if RunRev implemented threading into RR for 3.0, we would have<br>>   this process written into just one server 
 application. It's one<br>>   thing that differentiates Java from RR...<br><br>That's mainly marketing... Even if unofficial, the JAVA 1.4 best <br>practices recommandation is to never exced 3 simultaneous bytecode <br>threads per web-services (aka : best to let dedicaded parts of the <br>system handle such kind of tasks, including the Posix kernel's <br>multi-theading features (very well suited under Linux), the Apache and <br>ACID-DB servers ones).<br><br>> BUT wait a millisecond,<br>>   requesting web urls is threaded and could be used also as a<br>>   transaction protocol for any client over port 80 couldn't it?<br><br>True. Apache is build to handle that all for us (in synchronious mode) <br>in opening a new thread for each incoming request.  By experience, the <br>MC/Rev applications servers are just best coached in this way than by <br>any internal transcript dedicated code and, because, the WAS works, in <br>practice,; always faster than the DB backend, there is no wait at all, <br>each transaction thread after an other.<br>><br>>   If well formed, im sure you can send xml or any data embeded into<br>>   an client-side html-form request on good old port 80!<br><br>100 times true !  Simplicity is there the best entry to build secure <br>and clean...<br><br>>   Using mysqlmgr in html, you can send loads of sql data via a form<br>>   to the server.<br>><br>> ;)<br><br>Cool and very "pedagogique" (as we say so much, there, in France) post <br>! Thanks, Xavier :D<br><br>Best, Pierre<br>><br>><br>>> -----Original Message-----<br>>> From: use-revolution-bounces at<br>>> [mailto:use-revolution-bounces at]On Behalf Of Andre<br>>> Garzia<br>>> Sent: Tuesday, August 03, 2004 00:08<br>>> To: How to use Revolution<br>>> Subject: Re: Advise on enterprize application.<br>>><br>>><br>>><br>>> On Aug 2, 2004, at 6:51 PM, Mark Wieder wrote:<br>>><br>>>> Andre-<br>>>><br>>>> I'd have to agree with Trevor here that a multi-tiered approach is <br>>>> the<br>>>> way to go. I think you'll have an easier time of it than trying to<br>>>> stuff everything into a giant rev app (not to mention an easier time<br>>>> doing maintenance in the long run).<br>>>><br>>><br>>> Mark,<br>>><br>>> Thanks! Already on that path! I just need to know how to make that<br>>> database library work in the mc engine... it's not there...<br>>><br>>> Andre<br>>><br>>><br>>>> --<br>>>> -Mark Wieder<br>>>>  mwieder at<br>>>><br>>>><br>>> --<br>>> Andre Alves Garzia ð 2004<br>>> Soap Dog Studios - BRAZIL<br>>><br>>><br>>> _______________________________________________<br>>> use-revolution mailing list<br>>> use-revolution at<br>>><br>><br>> _______________________________________________<br>> use-revolution mailing list<br>> use-revolution at<br>><br>><br>><br>-- <br>Bien cordialement, Pierre Sahores<br><br>100, rue de Paris<br>F - 77140 Nemours<br><br>psahores+ at<br><br>GSM:   +33 6 03 95 77 70<br>Pro:      +33 1 64 45 05 33<br>Fax:      +33 1 64 45 05 33<br><br>WEB/EAI services & ACID DB over IP<br>"Mutualiser les deltas de productivité"<br><br>_______________________________________________<br>use-revolution mailing list<br>use-revolution at<br><br>

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