Thomas, Jonathan Thanks for your responses. Well, the problem I currently face, supposing that I am using the correct terminology, is how to maintain a failed HTTP request; (For example, a file download request). Do you aware of any solutions regarding this issue? What is your suggested plan in order to achieve such a solution? Does HAProxy help in this context? Thanks a lot.
*Ali Majdzadeh Kohbanani* *Managing Director* *Abshar Data Processing* *Tel:+982144160700 * * Tel/Fax: +982144160701 * *Cell:+989123614728* *[email protected] * *http://www.abshar.biz* 2013/6/4 Jonathan Matthews <[email protected]> > On 3 June 2013 22:36, Ali Majdzadeh <[email protected]> wrote: > > > > Hello All, > > I am totally new to HAProxy. What I am looking for is a solution for > HTTP load balancing and according to what I have read about HAProxy, I > think this is the right choice. > > Hi Ali. I've found HAProxy to be a really good HTTP load-balancer. > Here's my unofficial take on your questions. > > > Concerning HTTP, HAProxy is session-aware. Does this mean that all the > requests initiated from a specific client goes only to a specific back-end > server? > > This can be configured, yes. > > > What happens if suddenly the back-end server fails? > > Your backend should expose a health check URI that can be requested by > HAProxy frequently (very frequently, if possible). If it stops > returning a 200, then that backend will stop receiving new requests. > The details of this are all configurable - timeouts, number of failed > health checks required to fail a backend, etc. > > > For example, suppose that a user is downloading a file from a back-end > web server and the same file exists on another back-end web server. The > load on these two servers is balanced by HAProxy. Now, what happens if the > first web server dies whilst the file is being downloaded? > > The client will receive an incomplete download. This is unavoidable - > any solution mitigating this would have to be highly coupled to the > backend service being provided, as a generic solution would almost > certainly not be HTTP RFC compliant. > > > Does the download continues from the second server from where it was > interrupted? > > No. Another request will need to be made, through HAProxy (and not > /by/ HAProxy) to the backend. > > > I am not sure whether I have got the correct understanding of > session-awareness feature in HAProxy. I do appreciate your comments. > > I don't think that HAProxy's sessions are related to the kind of > in-request failure you seem to be concerned about. But I haven't run > the current 1.5 development version, so I may be out of touch with > what it does in this area. > > Regards, > Jonathan > -- > Jonathan Matthews // Oxford, London, UK > http://www.jpluscplusm.com/contact.html > >
