I have an MVC3 application which is working fast in my dev environment (even when pointed at the production database). However, when I publish the application and move it onto the production iis7 environment it runs at a snails pace. I understand that the inital load can take a few seconds as the application pool starts up, but this is taking 20+ seconds. Then will be fast for a few clicks and the next click will again take 20+ seconds.
I've put in the MVCMiniPorifler and it doesn't look like the database is causing problems. But, I also can't see what is causing the problem. I can hit the same page multiple times and it comes back in a second or 2 and then suddenly that same page will take 20+ seconds to respond.
Has anyone seen this sort of behaviour before? Any help would be greatly appreciated and I'm not sure what to try next.
It's possible that the other web apps running on your production server are locking required resources. Is there a common file or folder that multiple sites utilize? Are you sharing the app pool between any of the sites?
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We are working on an ASP.NET 5 Web API project that is in production now but we are experiencing an issue where it becomes unresponsive intermittently throughout the day.
A few notes about the application architecture. It is an ASP.NET Web API project using a MariaDB database on a separate EC2 instance within the same private network. The connection string uses the private IP of the database server to avoid any name resolution issues. The site is hosted via IIS 10.
The application itself has been developed carefully following the best practices provided by Microsoft. Heavy focus on async operations, minimizing query response times and offloading more expensive operations into background services.
The app is extremely responsive. It performs with sub 100ms responses on almost all requests, even the more complicated requests, and all the way up until it becomes unresponsive this high level of performance remains the same. We tend to see between 10-30 requests per second and 300-500 select queries per second at peak usage so not too extreme. However, randomly (2-3 times over a 24 hour period) it will begin hanging on requests and simply not respond to the request. During this time, the database is still extremely responsive and we are never over 300 connections out of our 512 connection limit.
The resources on the application server itself are never really taxed much at all. The CPU never gets above ~20% and the memory usage sits around 20-30%.
If I were to stop the site in IIS and start it again while this is happening, it will quickly come back online. If I don't it will be down for a few minutes until IIS finally kills it due to a failed health check. There are no real errors generated as a response to the issue other than typical errors caused by the hanging of the process such as connection terminated errors. The only thing I have seen before that gave me pause was the fact that there a few connection timeouts when getting the connection from the pool, but like I said, the connections to the server are never close to the limit.
Also, this app and version has been in production for months and it wasn't until the traffic volume started to grow that we started seeing these issues. At this point, I am at a loss for next steps of troubleshooting and I'm seeking suggestions.
In IIS App Pool advanced settings set Start Mode to AlwaysRunning
I never found a root cause for this issue, however, after updating to newer versions of .NET MVC this issue went away. My best guess is that changes with the Kestrel possibly resolved this issue, although, I have no idea what specific change that might have been. I have gone through the change logs a few times and didn't see anything that specifically jumped out at me.
I have an asp.net mvc4 web api interface that gets about 54k requests a day.
http://myserv.x.com/api/123/getstuff?whatstuff=thisstuff
I have 3 web servers behind a load balancer that are setup to handle the http requests.
On average response times are ~300ms. However, lately something has gone awry (or maybe it has always been there) as there is sporadic behavior of response times coming back in 10-20sec. This would be for the same request hitting the same server directly instead of through the load balancer.
GIVEN:
- System has been passed down to me so there may be gaps with IIS confiuration, etc,.
- Database: SQL Server 2008R2
- Web Servers: Windows Server 2008R2 Enterprise SP1
- IIS 7.5
- Using MemoryCache aggressively with Model and Business Objects with eviction set to 2hrs
- Looked at the logs but really don't see anything significantly relevant
- One application pool...no other LOB applications running on this server
Assumptions & Ask:
Somehow I'm thinking that something is recycling the application pool or IIS worker threads are shutting down and restarting thus causing each new request to warmup and recache itself. It's so sporadic that it's tough to trouble shoot right now. The same request to the same server comes back fast as expected (back to back N requests) since it was cached in about 300ms....but wait about 5-10-20min and that same request to the same server takes 16seconds.
I have limited tracing to go by as these are prod systems so I can only expose so much logging details. Any help and information attacking this or similar behavior somebody else has run into is appreciated. Thx
UPDATE:
The w3wpe.exe process grows to ~3G. Somehow it gets wiped out and the PID changes so itself or something is killing it every 3-4min I see tons of warnings in my webserver (IIS) log:
A process serving application pool 'MyApplication' suffered a fatal
communication error with the Windows Process Activation Service. The
process id was '1732'. The data field contains the error number.
After 4-5 days of assessing IIS and configuration vs internal code issues I finally found the issue with little to no help with windbg or debugdiag IIS tools. Those tools contain so much information even with mini dumps or log trace stacks that they can be red herrings. Best bet was to reproduce it by setting up a "copy intelligently" instance of a production system, which we did not have at the time and took a bit for ops to set something up.
Needless to say the problem had to do with over cacheing business objects. There was one race condition where updates on a certain table were updating an attribute to that corresponding business object (updates were coming from multiple servers) which was causing an OOC stackoverflow that pretty much caused the cacheing to recursively cache itself to death thus causing the w3wp.exe process to die and psuedo-recycle itself. It was one of those edge cases that was incredibly hard to test and repro in a non-production environment.
I have ASP.NET MVC app which accept file uploads and has result pooling using SignalR. The app hosted on Prod server with IIS7, 4 Gb Ram and two cores CPU.
The app on Dev server works perfectly but when I host it on Prod server with about 50 000 users per day the app become unrresponsible after five minutes of running. The web page request time increase dramatically and it takes about 30 seconds to load one page. I have tried to record all MvcApplication.Application_BeginRequest event call and got 9000 hits in 5 minutes. Not sure is this acceptable number of hits or not for app like this.
I have used ANTS Performance Profiler(not useful in Prod app profiling, slow and eats all memory) to profile code but profiler do not show any time delay issues in my code/MSSQL queries.
Also I have tried to monitored CPU and RAM spike problems but I didn't find any. CPU percentage sometimes goes to 15% but never up and memory usage is normal.
I suspect that there is something wrong with request or threads limits in ASP.NET/IIS7 but don't know how to profile it.
Could someone suggest any profiling solutions which could help in this situation? Tried to hunt the problem for two week already without any result :(
You may try using the MiniProfiler and more specifically the MiniProfiler.MVC3 NuGet package which is specifically created for ASP.NET MVC applications. It will show you all kind of useful information such as the time spend for different methods in the execution of the request.
We're running 3 different Drupal (Pressflow to be specific) sites on the same server. The 2nd and 3rd sites were cloned from the first one and load just fine. The first one, though, is taking a few seconds to connect and start sending data back from the server. Same box, same config (as far as we know), same modules, and generally the same theme. Here's what Pingdom shows...
Fast site:
http://i.stack.imgur.com/YZilC.png
Slow site:
http://i.stack.imgur.com/6Um1M.png
Edit: Those are from Pingdom, the yellow indicating "The web browser is waiting for data from the server"
The configs are the same, performance options same, server configs, as far as we can tell are the same. The delay occurs before any page elements are visible so it's not an on-page object problem or a page speed problem.
Could this be a config issue with the server? Where should we be investigating?
Thanks in advance!
I would try increasing the size of your MySQL cache. It's possible the fast sites have their particular queries cached and the slow site has a query that doesn't quite fit the cache, so the MySQL query results need to be regenerated each time.
Just a guess!
I created two very simple Heroku apps to test out the service, but it's often taking several seconds to load the page when I first visit them:
Cropify - Basic Sinatra App (on github)
Textile2HTML - Even more basic Sinatra App (on github)
All I did was create a simple Sinatra app and deploy it. I haven't done anything to mess with or test the Heroku servers. What can I do to improve response time? It's very slow right now and I'm not sure where to start. The code for the projects are on github if that helps.
If your application is unused for a while it gets unloaded (from the server memory).
On the first hit it gets loaded and stays loaded until some time passes without anyone accessing it.
This is done to save server resources. If no one uses your app why keep resources busy and not let someone who really needs use them ?
If your app has a lot of continous traffic it will never be unloaded.
There is an official note about this.
You might also want to investigate the caching options you have on Heroku w/ Varnish and Memcached. These are persisted independent of the dynos.
For example, if you have an unchanging homepage, you can cache that for extended periods in Varnish by adding Cache-Control headers to the response. Then your users won't experience the load hit until they want to "do something" rather than when they arrive.
You should check out Tom Robinson's answer to "Scalability: How Does Heroku Work?" on Quora: http://www.quora.com/Scalability/How-does-Heroku-work
Heroku divides up server resources among many different customers/applications. Your app is allotted blocks of computing power. Heroku partitions based on resource demand. When you have a popular application that demands more power, you can pay for more 'dynos' (application containers) and then get a larger chunk of the pie in return.
In your case though, you are running a free app that few people--if any outside of you--are visiting/using. Therefore, Heroku cuts down on the resources you're getting by unloading your app--putting it in hibernation essentially--until there is a request made to your address. When that happens, and your app has been idling for a long time, it takes time to reload.
Add 1 extra dyno to keep your app from falling asleep, if that reload time is important.
I am having the same problem. I deployed a Rails 3 (1.9.2) app last night and it's slow. I know that 1.9.2/Rails 3 is in BETA on Heroku but the support ticket said it should be fine using some instructions they sent me.
I understand that the first request after a long time takes the longest. Makes sense. But simply loading pages that don't even connect to a DB taking 10 seconds sometimes is pretty bad.
Anyway, you might want to try what I'm going to do. That is profile my app and see how long it takes locally. If it's taking 400ms then something is wrong. But if I get 50ms locally and it still takes 10 seconds on Heroku then something is definitely wrong.
Obviously, caching helps but you only get 5MB for free and once again, with ONE person using the site, it shouldn't be that slow.
I had the same problem with every app I have put on via heroku's free account. Now there are options of adding dynos so that your app does not get offloaded while it is not being used for a while, you can also try using redis or memcached for caching. But I used a hacky solution for my small scale project, I basically built web scraper put it inside an infinite loop with sleep and tada the website actually had much better response times(I guess it was not getting offloaded because of the script).