Thanks Jason. The reply is insightful. I now try to set up dhis2 on a Tomcat cluster with nginx and mysql cluster altogether. Will let you know the result soon
*Nguyễn Ngọc Thành* On Sun, Sep 22, 2013 at 12:26 PM, Knut Staring <knu...@gmail.com> wrote: > I think we should get DHIS2 added to that list of systems (typically) > running on Tomcat. It is a MoinMoin wiki, so I thought I could just add us, > but it seems this is an "immutable" page.. > > > On Sun, Sep 22, 2013 at 7:19 AM, Jason Pickering < > jason.p.picker...@gmail.com> wrote: > >> Hi Thanh, >> >> First off, be sure you are aware of who you are dealing with in such a >> debate. These "commercial companies" are probably a lot better at you in >> selling products to people who do not need them than you are. This is after >> all, what they do. So, keeping that in mind, lets pick apart what they are >> saying. >> >> "DHIS2 is not built on and use well-know reliable solutions such as >> Microsoft Sharepoint, IBM Websphere, Oracle Bea Weblogic" >> >> No reason why you could not used DHIS2 with Websphere or Weblogic in >> theory. Of course, it would be a huge waste of money to plonk down money >> for these applications, when Apache Tomcat (which is free) will do the job >> just fine. DHIS2 is using Spring and not EJB, so there is simply no need >> for these products. As for Sharepoint, well, it is a totally different >> application stack, and not really interesting to debate about. Point is >> DHIS2 is built using Java and lots of standard open-source libraries used >> by lots of other projects (including commercial ones). So which application >> server it uses is really a mater of choice. You could take Tomcat, and it >> would work fine. You could also pay a company a lot of money for >> a licence for one of the products you mention. Here is a partial list of >> companies/projects using Tomcat, and the number is not small ( >> http://wiki.apache.org/tomcat/PoweredBy) >> >> >1. When multiple DHIS2 instances can be deployed in multiple servers >> (virtual or physical) and load balanced by a hard or soft balancer >> (nginxs), this can not solve the real >problem of distributed HTTP sessions >> like what can be done in Application Server, i.e. a logged in users >> connected to a instance and this instance die, how can they continue >> >without relogin. >> >Can using Application Server solve the problems without having to >> rewrite dhis2? >> >> >> Which Application Server? I guess my question here would be what is the >> impact of a clustered Tomcat instance crashing? OK, maybe the user has to >> login again. Maybe they loose a little bit of work at worst. So what? Not >> that this is not an impact, but would it justify even an attempt to >> implement a load-balanced clustered solution with some sort of failover >> protection transparent to the user? It would not really seem to be >> justified. >> >> >How are we going to solve this? Will we need to use commercial solutions >> like Terracotta BigMemory or IBM Data Grid? >> >> What is the point? This again sounds like a bit of a snake-oil argument >> here. These products are not going to help with the issue of an application >> server failing. . >> >> >3. I would like to know the typical deployment of dhis2 in other >> countries. Is that on one or multiple server, with or without database >> clusters? I heard that many countries go for >cloud but I am not sure if it >> is a single or multiple cloud servers? >> >> Most countries which I know of are using a rather modest server. Many are >> using the cloud, some are not. Many countries have everything on the same >> machine (database, application server, nginx) and separating the database >> and application server is fairly typical as well. But I could imagine >> there are some installations out there which are using clusters, but I >> would say this is probably not typical (yet) of most DHIS2 installations. >> >> >> >Can cloud provide us a single virtual but unlimited RAM and CPUs server? >> As if yes, then we don't have to worry about question 1, 2 because we can >> simple add 10000000 >GB RAM and 100000 CPUs to that cloud server. >> >> Well, for all intents and purposes, you could continue to increase the >> size of the server up to a certain size as required but I think the metrics >> you give there are pretty ridiculous.Why would you need that much RAM or >> CPU power? Even if it were physically possible which seems reasonable >> (although likely very very expensive) , it would generally not make much >> sense to do this. Probably better to break the system up into smaller >> pieces instead. Using many small servers to distribute the process is >> typically the favored approach, instead of having one big massive machine. >> >> Anyway, there are a few thoughts off the top of my head. In summary, >> there is simply no need for the commercial products you mention in the vast >> majority of use cases we have come across. Not to say that they do not >> exist, but I would press these "companies" for more details on how these >> are actual requirements, and not simply invented hypothetical cases which >> could potentially be used to make a sale of unneeded licences. >> >> Regards, >> Jason >> >> >> >> On Sun, Sep 22, 2013 at 3:14 AM, Ngoc Thanh Nguyen < >> thanh.hispviet...@gmail.com> wrote: >> >>> Hi all, >>> >>> Some commercial affiliated companies want to kick dhis2 out so they made >>> the following arguments: "DHIS2 is not built on and use well-know reliable >>> solutions such as Microsoft Sharepoint, IBM Websphere, Oracle Bea Weblogic" >>> >>> When most of this is wrong they have some valid points that we need to >>> be prepared in order to fight back. I would like to get your ideas on >>> >>> 1. When multiple DHIS2 instances can be deployed in multiple servers >>> (virtual or physical) and load balanced by a hard or soft balancer >>> (nginxs), this can not solve the real problem of distributed HTTP sessions >>> like what can be done in Application Server, i.e. a logged in users >>> connected to a instance and this instance die, how can they continue >>> without relogin. >>> >>> Can using Application Server solve the problems without having to >>> rewrite dhis2? >>> >>> How are we going to solve this? Will we need to use commercial solutions >>> like Terracotta BigMemory or IBM Data Grid? >>> >>> 2. For database scale, with one database instances installed on single >>> server. it has the risk of data loss. We can use database clusters to >>> address this issue, and data on clusters mostly rely on memory. My question >>> is how this cluster will work with distributed sessions described in >>> question 1. >>> >>> 3. I would like to know the typical deployment of dhis2 in other >>> countries. Is that on one or multiple server, with or without database >>> clusters? I heard that many countries go for cloud but I am not sure if it >>> is a single or multiple cloud servers? >>> >>> Can cloud provide us a single virtual but unlimited RAM and CPUs server? >>> As if yes, then we don't have to worry about question 1, 2 because we can >>> simple add 10000000 GB RAM and 100000 CPUs to that cloud server. >>> >>> Thanks in advanced. >>> >>> Thanh >>> >>> >>> >>> >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~dhis2-devs >>> Post to : dhis2-devs@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~dhis2-devs >>> More help : https://help.launchpad.net/ListHelp >>> >>> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~dhis2-devs >> Post to : dhis2-devs@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~dhis2-devs >> More help : https://help.launchpad.net/ListHelp >> >> > > > -- > Knut Staring > Dept. of Informatics, University of Oslo > +4791880522 > http://dhis2.org >
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