With the App Fabric Cache there are limits to the number of transactions per hour. Is there any way to monitor this? Firstly for testing, to find out how much cache we will need, and primarily so we don't hit the limit and have the site go down because we can't access the cache any more.
yes, you can use the Azure Application Manager as explained in this blogpost:
http://blogs.msdn.com/b/appfabric/archive/2011/06/20/introducing-windows-azure-appfabric-applications.aspx
there are some opensource tools available on codeplex as well:
http://www.codeplex.com/site/search?query=azure%20monitor&ac=3
i usually stick to the azure provided tools..
At the moment there is nothing in the management portal or in any in of the APIs that you can use to determine how many transactions you've used against the cache in any given hour (or how many connections you're using, the other limiting factor when using app fabric cache).
If this is particularly important you might try building a wrapper around cache access and use a scalable counter which increments every time you perform a transaction.
Related
I have a local VPS that hosting and providing my Node.js REST API in my country.
However soon I will need to open it for different countries.
That means that clients from remote will ask for my services.
Since they are far it will be probably slow connection.
How can I avoid this? Maybe I need more servers located in their countries too, but still, how the data could be shared over one DB?
I do not looking for a full tutorial for how to do that (could be nice to have) but I am looking for get info about the methodology of this.
What do you recommend to do, keep buying servers in remote countries, sharing their data between them someway, or maybe choose to use some cloud service like Firebase? How cloud services work in first place?
Without going into too much detail for each item, here are some keypoints in which I think you should focus your on learning to solve your problem.
For data storage - look into firestore (not the json database) as firestore is globally scaleable.
For your REST endpoints I would use google cloud functions, but without knowing the nature of your application its hard to say if its suitable. The key to being able to reach global scale is having cacheable endpoints. Then you are leveraging google's global CDN which is much faster than hitting the origin server. Note: The firebase cloud functions infrastructure WILL face cold start issues which may/may not be a problem for you.
Cache invalidation is a little lacking so you can leverage longer max-age cache settings but use either cache busing and/or the header stale-while-revalidate to help with this.
There is some great info here https://www.youtube.com/watch?v=dbV-293m1dQ that covers some of what I have mentioned in more detail.
There is a need to cache objects to improve the perf of my Azure function. I tried .NET ObjectCache (System.Runtime.Caching) and it worked well in my testing (tested with upto 10min cache retention period).
In order to take this solution forward, I have few quick questions:
What is the recycling policy of Azure function. Is there any default? Can it be configured?
What is the implication in the cost?
Is my approach right or are there any better solutions?
Any questions that you may know, please help.
Thank you.
Javed,
An out-of-process solution such as Redis (or even using Table storage, depending on the workload) would be recommended.
As a rule of thumb, functions should be stateless, particularly if you're running in the dynamic runtime, where scaling operations (up and down) could happen at any time and your host is not guaranteed to stay up.
If you opt to use the classic hosting, you do have a little more flexibility, as you can enable the "always on" feature, but I'd still recommend the out-of-process approach. Running in the classic mode does have a cost implication as well, since you're no longer taking advantage of the consumption based billing model offered by the dynamic hosting.
I hope this helps!
If you just need a smallish key-value cache, you could use the file system. D:\HOME (also found in the environment variable %HOME%) is shared across all instances. I'm not sure if the capacities are any different for Azure Functions, but for Sites and WebJobs, Free and Shared sites get 1GB of space, Basic sites get 10GB, and Standard sites get 50GB.
Alternatively, you could try running .NET ObjectCache in production. It may survive multiple calls to the same instance (file system or static in-memory property). Note, this will not be shared across instances though so only use it as a best effort cache.
Note, both of these approaches pose problems for multi-tenant products as it could be an avenue for unintended cross-tenant data sharing or even more malicious activities like DNS cache poisoning. You'd want to implement authorization controls for these things just as if they came from a database.
As others have suggested, Functions ideally should be stateless and an out of process solution is probably best. I use DocumentDB because it has time-to-live functionality which is ideal for a cache. Redis is likely to be more performant especially if you don't need persistence across stop/restart.
I am conducting some research on emerging web technologies and have created a very simple Azure website which makes use of web sockets and mongo db as the database. I have managed to get all the components working together and now must perform load testing on the application.
The main criteria is the maximum user load that the app can support, at the moment there is 1 web role instance, so probably I would need to test the max user load for that instance, then try with 2 instances and so on.
I found some solutions online such as Loadstorm, however I cannot afford to pay to use these services so I need to be able to do this from my own development machine OR from another cloud service.
I have come across Visual Studio Load Tests and they seem quite useful, however it seems they require VS Ultimate and an active msdn subscription - the prerequisites are listed here. Also, from this video which shows the basics of load tests, it seems like these load tests are created completely separately from the actual web project, so does that mean I can only see metrics related to the user? i.e. I cannot see the amount of RAM being used, processor etc.
Any suggestions?
You might create a Linux virtual machine in Azure itself or another hosting provider and use ApacheBench (ab) or JMeter to do simple load testing on your application. Be aware that in such a setup your benchmark servers may be a bottleneck themselves.
Another approach is to use online load testing services wich allow some free usage, such as:
loader.io, by SendGrid Labs
LoadStorm
Blazemeter
Blitz
Neotys
Loadimpact
For load-testing, LoadStorm is very reasonably priced, especially compared to on-premises software (and has a free tier with up to 25 virtual clients). You can install code such as jmeter, but you'll still need machines (or vm's) to host and run it from, and you need to make sure that the load-generator machines aren't the bottleneck in your tests.
When you run your tests, you may want to consider separating your web tier from MongoDB. MongoDB will consume as much memory as possible (as that's what gives MongoDB its speed). In a real-world scenario, you'll likely have MongoDB in its own environment. So for your tests, I'd consider offloading MongoDB to its own instance(s), and 10gen has a Worker Role setup that's fairly straightforward to install.
Also remember that NIC bandwidth is 100Mbps per core, which could be a limiting factor on your tests, depending on how much load you're driving.
One alternative to self-hosting MongoDB: Offload MongoDB to a hoster such as MongoLab. This will allow you to test the capacity of your web app without worrying about the details around MongoDB setup, configuration, optimization, etc. Currently MongoLab offers their free tier hosted in Azure, US West and US East data centers.
Editing my response, didnt read the question carefully.
Check out this thread for various tools and links:
Open source Tool for Stress, Load and Performance testing
If you are interested in finding the performance counters of the application under test you can revisit some of the latest features added to Visual Load Cloud base load test.
http://blogs.msdn.com/b/visualstudioalm/archive/2014/04/07/get-application-performance-data-during-load-runs-with-visual-studio-online.aspx
To get more info on Visual Studio Cloud Load Testing solution - https://www.visualstudio.com/features/vso-cloud-load-testing-vs
I'm working on Integration project where third party will call our web service in Azure. For performance reason I would like to store 2 table data (more than 1000 records) on to the app fabric cache.
Could anyone please suggest if this is the right design pattern?
Depending on how much data this is (you don't mention how wide the tables are) you have a couple of options
You could certainly store it in the azure cache, this will cost though.
You might also want to consider storing the data in the http runtime cache which is free but not distributed.
You choice would largely depend on the size of the data, how often it changes and what effect is caused if someone receives slightly out of date data.
I believe that the mvc mini profiler is a bit of a 'God-send'
I have incorporated it in a new MVC project which is targeting the Azure platform.
My question is - how to handle profiling across server (role instance) barriers?
Is this is even possible?
I don't understand why you would need to profile these apps any differently. You want to profile how your app behaves on the production server - go ahead and do it.
A single request will still be executed on a single instance, and you'll get the data from that same instance. If you want to profile services located on a different physical tier as well, that would require different approaches; involving communication through internal endpoints which I'm sure the mini profiler doesn't support out of the box. However, the modification shouldn't be that complicated.
However, would you want to profile physically separated tiers, I would go about it in a different way. Specifically, profile each tier independantly. Because that's how I would go about optimizing it. If you wrap the call to your other tier in a profiler statement, you can see where the problem lies and still be able to solve it.
By default the mvc-mini-profiler stores and delivers its results using HttpRuntime.Cache. This is going to cause some problems in a multi-instance environment.
If you are using multiple instances, then some ways you might be able to make this work are:
to change the Http Cache to an AppFabric Cache implementation (or some MemCached implementation)
to use an alternative Storage strategy for your profile results (the code includes SqlServerStorage as an example?)
Obviously, whichever strategy you choose will require more time/resources than just the single instance implementation.