Web Farm Timeouts crashing Site

What version are you running? There are several issues in v8, v8.1, v8.2 and v9 which are resolved in v10. We recently upgraded a site to v10 and it resolved 99.9% of the webfarm issues we had.

Hi Brenden,

I am currently running version 10.

Cheers, Jay

Can you explain your setup from a server standpoint as well as Kentico Web Farm configuration?

Yeah sure.

We have two web servers and two database servers with a load balancer directly traffic as you would expect.

The web farm mode is set to manual and we have entered the keys into the web configs for Server001 and Server002 with everything ticked for allow synchronization for.

The site runs fine initially orders go through, task are processed on the bus, web server tasks are processed as expected. But the more traffic that comes through the site the worse things become until the site eventually crashes and I have to restart both servers.

We get time out errors of: [DataConnection.HandleError]: Query: SELECT * FROM CMS_WebFarmServer Caused exception: Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

Are you mirroring those databases or do you have one shared database between the 2 web servers?

Any particular reason you are defining the servers and not letting Kentico automatically handle them? I'd highly recommend making that change to automatic and let Kentico handle things better. If you still want to assign server names to scheduled tasks, you can but I'd recommend making the change to auto.

Hi Brendan,

I have followed your advise and set the set up to auto. It seems to be going ok but I need to perform some load tests and make sure the site is running as I expected.

With regards the scheduled tasks (for example Execute Search Tasks) I have multiple tasks set up for each server. Is this necessary? Or do I still need multiple scheduled tasks for each server?

Thanks, Jay

You don't NEED them but in some cases it doesn't hurt. Kentico does a great job of determining which server to use and execute those tasks on.

Hi Brendan,

In terms of the site crashing this now seems to be resolved so thanks for your help. The only problem I now have is that the lucene indexes are not being updated? Any ideas?

Thanks, Jay

Each server will rebuild their own search indexes. You will want to clean up the search index folders and attempt a rebuild of them.

/App_Data/CMSModules/SmartSearch/<searchindexname>

In each of those folders make sure you clean up an lock files.

All of the products and previously created users are there in the indexes. So if I switch over to auto web farm (server names change) I can still search for products etc. If I add something new the index is not updated and the new registered user is not returned for example. I'm sorry but I don't see how a complete rebuild of the indexes will then fix this problem? Surely if the the server could not update the index I would not be getting anything returned in my search results in the first place?

If the indexes are not being updated you need to make sure there are no lock files in the file system. Rebuilding the indexes will allow the system to clean things up AFTER you clean the lock files out of the file system.

Check here: /App_Data/CMSModules/SmartSearch/<searchindexname>

Thanks Brendan. There doesn't seem to be any lock files hanging around on either server. I will try completely deleting all of the Smart Search indexes and rebuilding them.

Just the files, not the index within Kentico. Make sure you do it on both servers as well. And most importantly, give it time.

Yes sorry that is what I meant. I am going to delete all of the files and then rebuild them. I will be doing this before I leave the office and let it run over night as you said it will take time.

Hi Brendan,

I have rebuilt my indexes over night. I then created an account this morning through the site created an address for that account but it was not returned in my search results? When I have the manual web farm set up I can create a new account assign an address to that account and the account immediately shows up in the search results. Any thoughts?

Thanks, Jay