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What is best approach to sync data between 1000 wpf(with offline mode) / SQL Server app to central website (SQL Server ) and vice versa?

We have an online food ordering management system with 1000 registered restaurants in this application. Every restaurant has its own product, category.
I want to create another desktop WPF application named Epos (Electronic point of sale). This application has both an online and offline mode. I am concerned about the data sync between 1000 the customer epos and the central, online food ordering system. If an order is placed from a desktop PC it should sync to website. If any customer order is placed using the website it should sync to their desktop app.
Website: Asp.net mvc and SQL Server database
Desktop Epos: WPF app plus SQL Server Express
We saw some solutions on the internet :
Microsoft Sync Framework
What is the best approach to solve this problem?
Sorry for my bad English

Too broad but most likely you don't even need db on client
I would just load the objects in a List and use LINQ
Unless you have some really massive List
I would just synch down by demand on the client
And have it synch everytime it uploads an order
You can also have a watch on the db to get notified but not sure how that would work with a service
If the Internet went down you would still have what is in memory so you cannot shut the app down. But I am amazed you have restaurants with unreliable Internet. Do they have reliable power?

Azure solution design guidelines

There are too many options to chose from in Microsoft Azure when planning application design. Azure itself not stands still, looks like many options added recently. I'm a pretty nooby solo developer so I need some entry points to choose architecture.
The application consists of next parts:
1. Database
Classic SQL database is already implemented with Azure SQL database.
2. Server-side application. (architecture refactor needed)
For now application is a .NET C#/WPF desktop application hosted on classic Azure Virtual Machine with Windows Server onboard.
This is an always-running scheduler that performs kind of tasks one by one.
Tasks are mainly long-running works getting some data from Web, CPU-bound proccessing with recieved data, working with the DB.
It feels like its kind of ancient and wrong design (having in mind amount of azure features):
a) The application really don't need a GUI, just ability to control scheduler's status required.
b) Logically some kind of tasks can be performed simultaneously, and some of them must wait others to finish before start. Now all of tasks performed one by one, that caused by virtual machine performance limit. I think there must be a way to achieve parallel working and control results on higher level of abstaction than inside desktop app. I wanna somehow move scheduling logic to level up. (Maybe IaaS->Paas goes here?)
3. Client applications.
Client applications. Registered users work with the DB.
Here questions:
Which server-side application design should be chosen in this case, what Azure features required?
Is there an Azure built-it abilities to manage registered users accounts, or only way is to implement it as a part of application?

Did you explore other storage options or SQL database is what you need?
lets start from scratch:
STORAGE:you can choose from
1. Storage - Blob, Table, Queue, and File storage and disks for VM
2. SQL database - relational database service in the cloud based on the market leading Microsoft SQL Server engine, with mission-critical capabilities
3. Document DB - schema-free NoSQL document database service designed for modern mobile and web applications
4. StorSimple- integrated storage solution that manages storage tasks between on-premises devices and Microsoft Azure cloud storage
5. SQL data Warehouse- enterprise-class distributed database capable of processing petabyte volumes of relational and non-relational data
6. Redis Cache- High throughput, consistent low-latency data access to build fast, scalable applications
7. Azure Search- Search-as-a-service for web and mobile app development
SCHEDULAR: You can pick from
1. Virtual Machine
2. Cloud Service (worker role): you have more control over the VMs. You can install your own software on Cloud Service VMs and you can remote into them.
3. Batch: Cloud-scale job scheduling and compute management
4. Service Fabric: distributed systems platform used to build scalable, reliable, and easily-managed applications for the cloud
5. App Service: Scalable Web Apps, Mobile Apps, API Apps, and Logic Apps for any device
CLIENT: you can try out
1. Web Apps
2. Cloud Service (web role)
Use this link as one stop shop for all Azure services beautifully categorized based on functionality. From here you can pick and choose various services and amp it to your app's requirement.
MASTER LIST: http://azure.microsoft.com/en-in/documentation/

Advice on options for shared database for distributed c# application

I'd like to know my options for the following scenario:
I have a C# winforms application (developed in VS 2010) distributed to a number of offices within the country. The application communicates with a C# web service which lies on a main server at a separate location and there is one database (SQL Server 2012) at a further location. (All servers run Windows Server 2008)
Head Office (where we are) utilize the same front-end to manage certain information on the database which needs to be readily available to all offices - real-time. At the same time, any data they change needs to be readily available to us at Head Office as we have a real-time dashboard web application that monitors site-wide statistics.
Currently, the users are complaining about the speed at which the application operates. They say it is really slow. We work in a business-critical environment where every minute waiting may mean losing a client.
I have researched the following options, but do not come from a DB background, so not too sure what the best route for my scenario is.
Terminal Services/Sessions (which I've just implemented at Head Office and they say it's a great improvement, although there's a terrible lag - like remoting onto someones desktop, which is not nice to work on.)
Transactional Replication (Sounds like something quite plausible for my scenario, but would require all offices to have their own SQL server database on their individual servers and they have a tendency to "fiddle" and break everything they're left in charge of!) Wish we could take over all their servers, but they are franchises so have their own IT people on site.)
I've currently got a whole lot of the look-up data being cached on start-up of the application but this too takes 2-3 minutes to complete which is just not acceptable!
Does anyone have any ideas?

With everything running through the web service, there is no need for additional SQL Servers to be deployed local to the client. The WS wouldn't be able to communicate with these databases, unless the WS was also deployed locally as well.
Before suggesting any specific improvements, you need to benchmark where your bottlenecks are occurring. What is the latency between the various clients and the web service, and then from the web service and the database? Does the database show any waiting? Once you know the worst case scenario, improve that, and then work your way down.
Some general thoughts, though:
Move the WS closer to the database
Cache the data at the web service level to save on DB calls
Find the expense WS calls, and try to optimize the throughput
If the lookup data doesn't change all that often, use a local copy of SQL CE to cache that data, and use the MS Sync Framework to keep the data synchronized to the SQL Server
Use SQL CE for everything on the client computer, and use a background process to sync between the client and WS
UPDATE
After your comment, two additional thoughts. If your web service payload(s) is/are large, you can try adding compression on the web service (if it hasn't already been implemented).
You can also update your client to do the WS calls asynchronously, either in a thread or if you are using .NET 4.5 using async/await. This would at least allow the client to use the UI, but wouldn't necessary fix any issues with data load times.

online database for C# window application

I'm going to develop a POS system for medium scale company
and the requirement for me is to make all data on time for all of their branches
while in my mind, move the server from local to web would solve this problem
but, i never done any online server for window application
may i know what is the best option for use as secure database ?
such as SQL can handle this well ?
i tried to google but all of the result return is not what i want
may i know what will you do when you facing this problem ?
my knowledge on coding is just VB and CS
also SQL for database
i would like to learn new if there is better option
i hope it is impossible to access by anonymous and it is store secure at back-end only

What you probably want to do is create a series of services exposed on the internet and accessed by your application. All database access would be mediated by these services. For security you would probably want to build them in WCF and expose them through IIS. Then your Windows application would just call these services for most of its processing.
If you design it properly you could also have it work with a local database as well so that it could work in a disconnected manner if, for example, your servers go down.

Typically you don't move the server off of the site premises.
The problem is that they will go completely down in the event your remote server is inaccessible. Things that can cause this are internet service interruption (pretty common), remote server overloaded (common enough), basically anything that can stop the traffic between the store location and your remove server will bring them to their knees. The first time this happens they'll scream. The second time and they'll want your head due to the lost sales.
Instead, leave a sql server at each location. Set up a master sql server somewhere. Then set up a VPN connection between the stores and this central office. Finally, have the store sql boxes do merge replication with the central office. Incidentally, don't use the built in replication, but an off the shelf product which specializes in replicating sql server. The built in one can be difficult to learn.
In the event their internet connection goes dark the individual stores will still be able to function. It will also remain performant as all of the desktop app traffic is purely to the local sql box.
Solving replication errors is much easier than dealing with a flaky ISP.

I would recommend you to check Viravis Platform out.
It is an application platform that also can be used just as an online database for any .NET client with the provided SDK. It has its own generic windows and web clients and some custom web solutions for some specific applications.
You may be using it as a complete solution or as a secure online database backend.

What are the challenges in porting your existing applications to Microsoft Azure?

What are the challenges in porting your existing applications to Azure?
Here are few points I'm already aware about.
1) No Support for Session Affinity (Azure is Stateless) - I'm aware that Azure load balancing doesn't support Session Affinity - hence if the existing web application should be changed if it has session affinity.
2) Interfacing with COM - Presently I think there is no support for deploying COM components to the cloud to interface with them - if my current applications need to access some legacy components.
3) Interfacing with other systems from the cloud using non-http protocols
Other than the above mentioned points, what are other significant limitations/considerations that you are aware off?
Also, how these pain points are addressed in the latest release?

our biggest challenge is the stateless nature of the cloud. though we've tried really really hard, some bits of state have crept through to the core and this is what is being addressed.
the next challenge is the support of stale data and caching as data can be offline for weeks at a time. this is hard regardless.

Be prepared for a lengthy deployment process. At this time (pre-PDC 2009), uploading a deployment package and spinning up host services sometimes has taken me more than 30 minutes (depends on time of day, size of package, # of roles, etc).
One side effect of this is that making configuration changes in web.config files is expensive because it requires the entire app package to be re-packaged and re-deployed. Utilize the Azure configuration files instead for config settings - as they do not require a host suspend/restart.

My biggest problem with Azure today is operability with other OS’es. Here I am comparing Azure to EC2/Rackspace instances (Even though Azure as PAAS offers a lot more than them e.g. load balancing, storage replication, geographical deployment etc in a single cheap package).
Even if you consider me as a BizSpark startup guy, I am not inclined to run my database on SqlAzure (Sql2005 equivalent) since I can’t accept their pricing policy, which I’ll have to bear three years after of the BizSpark program. Now they don’t have an option for MySql or any other database. This to me is ridiculous for an SME. With EC2 I can run my MySql instance on another Linux VM (obviously in the same network. Azure gives you the capability to connect to network outside theirs, but that is not really an option)
2nd. This is again is related to using *nix machines. I want all my caching to be maintained by Memcached. With asp.net 4 they have even given us out of the box memcached support through extensible output caching. The reason why I am adamant about memcached is the eco system it provides. E.g.: Today I can get memcached with persistent caching as an add-on. This will even give me the opportunity to store session data with memcached. Additionally I can run map reduce jobs on the IIS logs. This is done using cloudera images on EC2. I don’t see how I can do these with Azure.
You see, in the case of Amazon/Rackspace I can run my asp.net web app on a single instance of Windows Server 2008 and the rest on *nix machines.
I am contemplating running my non hierarchical data (web app menu items) on CouchDb. With Azure I get the Azure table. But I am not very comfortable with that ATM. With EC2 I can run it on the same MySql box(don't catch me on this one :-)).
If you are ready to forget these problems, Azure gives you an environment with a lot of grunt work abstracted. And that’s a nice thing. Scaling, loading balancing, a lot of very cheap storage, CDN, storage replication, out of the box monitoring for services through Fabric Controller etc among these. With EC2/Rackspace you’ll have to hire a sysadmin shelling $150k PA to do these things (AFAIK Amazon provides some of these feature at additional cost).
My comparisons are between azure and Amazon/Rackspace instances (and not cloud). For some this might seem like apples and orange. But azure does not provide you with instances. Just the cloud with their customized offerings…

My biggest problem is/was just signing up and creating a project. And that's how far it got over the last month.
Either I am doing something very wrong, or that site is broken most of the time.

One important challenge is the learning curve, lack of experienced developers, the time it takes to become productive .
This happens with all technologies, but with the cloud there is a fundamental change in how somethings are done.

If your application needs a database, I'm not sure that Windows Azure has a relational database (right now)
Also, there are other cloud computing providers that can offer you more options in configuring your virtual machine for example, it really depends on what you actually need and want.