I have to configure a (transactional) replication where it will have one distributor(publisher too) and more 6 servers that will be the subscribers.
The problem is: I never configured something like that, and after a whole week looking for a tutorial for do this, I decided to ask here because it's a task harder than I've imagined.
I already tried the MSDN tutorials, but without success. I know how to create a publication and subscribe it, but I don't know how to synchronize it with IIS(Internet Information Service).
The intention is: Sync it with IIS to the subscribers update the databases via web.
Note: I already tried ALL the MSDN tutorials. None of them worked.
So, I'm asking for any other way to do this.
Thanks in advance.
(I'm using Sql Server 2005 on Windows Server 2003) :)
Seems like web synchronization in SQL Server is available only for merge replication, not transactional too.
From MSDN:
Use the Web Synchronization Wizard to configure a Microsoft Internet
Information Services (IIS) server for Web synchronization, which
allows you to synchronize subscriptions to merge publications over an
Internet or intranet connection. For more information, see Web
Synchronization for Merge Replication and How to: Configure IIS
for Web Synchronization.
Much later edit, after reading comments.
Web synchronization supports indeed only merge replication.
In cases when the changes at the subscriber shouldn't propagate back to the publisher (design decision, whatever), the merge replication can be configured to mark published articles as read-only. Meaning that changes are not pushed back, similarly to transactional replication.
More to the point, merge replication supports a feature called Read-Only Articles (tables, etc), described here.
It says that:
Specify whether changes at the Subscriber are uploaded to the
Publisher. For applications in which some or all data should be
read-only at the Subscriber, download-only articles provide a
performance benefit.
Related
My management is evaluating non-Azure Microsoft Windows Service Bus (Azure is out of consideration for security reasons). It will be used to setup topic/subscription model with a number of WCF services with netMessagingBinding that we building, so I just have a few basic questions about that.
Are there any specific hardware requirements like dedicated server, dedicated database etc. for WSB to run in production environment?
It's easy to configure WCF service to listen on a specific topic subscription. Is there any way for WCF service to listen to multiple subscriptions?
Appreciate the answers.
You can install the service components and the databases all on one server (that is the default). However, for a number of reasons, we installed the services on a dedicated app server and then created the Service bus databases on an existing database server. The install package allows you to specify a different db server. Check this article for the minimum server requirements
Yes you can get one WCF service to listen to multiple subscriptions. You would need to create two (or more) System.ServiceModel.ServiceHost instances and then run them inside one process. For example we had one windows service running two ServiceHost's. Each host listened at a different queue and therefore implemented a different contract. This meant where queues were logically grouped we didn't need a new windows service per queue. You could do the same with subscriptions.
For question one, you will have to go through the exercise of hardware sizing. the good news is that WCF services can scale vertically, so you can add up servers if there were issues in handling client load.
To do hardware sizing you will have to make an estimate the expected load and then do performance/scalablity testing to figure the load bearing capacity of your serviceBus/services .
you could find a lot of resources for load testing like this one http://seroter.wordpress.com/2011/10/27/testing-out-the-new-appfabric-service-bus-relay-load-balancing/
once you do load testing and come up with the numbers, you can then do sizing using references like this one http://msdn.microsoft.com/en-us/library/bb310550.aspx
Is there any good way to integrate OpenLDAP or ApacheDS servers (or maybe another open-source LDAP server) with JMS to propagate LDAP database modification to another service?
Basically I need to have LDAP server cluster (several instances with master to master replication) and another standalone Java application, connected via a JMS server (e.g. ActiveMQ), so that:
All changes to LDAP data structure are sent to the Java app.
The Java app. can send messages to the LDAP database via JMS server to update LDAP data
I found out that there is a way to set up JMS replication for ApacheDS (https://cwiki.apache.org/DIRxSRVx11/replication-requirements.html#ReplicationRequirements-GeneralRequirements), but I am in doubt whether it will work in case we have a cluster of several ApacheDS masters + one JMS replication node to send all modifications to the cluster.
UPDATE: The page describing JMS replication for ApacheDS turned out to be 5 ears old, so currently the only way of replication in ApacheDS, I know about, is LDAP protocol based replication.
There IDM products that will perform what you are asking about.
I know NetIQs IDM products works well with JMS.
OpenLDAP and ApacheDS have a changeLog that you could use to determine the changes made.
You could then write some code to send the changes to JMS Queue.
I can't speak for ApacheDS, but OpenLDAP already contains a full-blown replication system, with about six different ways to configure it; in other words, you can do it perfectly well, and much more efficiently, without Java and JMS.
I am evaluating using NServiceBus as a SOA mechanism in our product. I'm looking into using the publish/subscribe pattern and my understanding is that the subscription service will store all subscriptions.
Does that mean that if my RavenDB server goes down then my publishers lose the ability to send to subscribers? Or is there a way for the publishers to cache the subscribers it has and if RavenDB were to go down then it would deliver to its known subscribers?
You can run the RavenDB server as a replicated node, to avoid this being a single point of failure.
The general pattern is for an endpoint to have a master node that acts as worker and distributor, and then the master node uses a Raven installation on that same server to store its subscriptions and saga storage.
So, it is a point of failure for that one endpoint, but other endpoints in the distributed system will use the Raven installs on their own servers. Thus, the system is kept distributed and the entire system does not have a single point of failure. RavenDB enables this because it is fairly easy to install it on any server.
Contrast this to SQL Server, which is frequently centralized, scaled up to the max, and even clustered in order to provide high availability. (Read: expensive!)
You can also run RavenDB in a Windows failover cluster where the nodes use a shared SAN for the RavenDB data files. If the active node dies, another takes over. Since the data is stored on the SAN, you shouldn't even notice it except the time it takes to start up the RavenDB windows service on the new node. Check out http://ravendb.net/docs/server/administration/fmc_configuration
This is also the recommended setup for High Availability when running with Distributors. http://docs.particular.net/nservicebus/scalability-and-ha/distributor/
I can imagine that the 'server' can be a machine/host but can be also a program like ftp server, smtp server, etc..
The 'service' on the other hand refers mainly to applications/programms..
Why can then for example the Sql Server cannot be called as Sql Service? It has the same semanthics. Or the other way round: MS Azure service: why it isn't called Azure Server? :)
I would say:
A server is expected to give a response
A service is not
Additionally, a service may include more than a server - it may well be an environment, hardware, SLA and more.
The services are features offered by the servers.
A server is a (possibly virtualized) piece of equipment that can be used to provide a service.
A service is something that you can use (usually remotely) that is provided by one or more servers.
The other difference is that these are really concepts at different levels of abstraction. Servers are concrete things. Services are abstract. Yet people mostly use services, and don't really care about what servers are used to implement them. Do you care about what servers are used to provide Google's web search service? No, you don't. Do you care about what servers are used to provide Amazon's cloud service? No, you don't.
A server is a a software program, or the computer on which that program runs, that provides a specific kind of service to client software running on the same computer or other computers on a network.
Per Microsoft - Windows Azure: operating system as an online service.
SQL Server is a Server, Any Stored Procedures or functions you write are Services. (A Query is a dynamic Service that has a life of just the call, it is sent to the Database, compiled, The Server executes the compiled code and returns the results)
I would say that there's no difference. They're used more-or-less interchangeably.
Or, if you prefer: you can come up with a definition, and someone will come up with a counter-example.
I am looking at using MSMQ as a solution to do asynchronous execution in my upcoming project. I want to know the differences between using WCF and frameworks like MassTransit or even hand written MSMQ client to place/read task off MSMQ.
Basically the application will be several websites (internal through LAN or external through the Internet) reading/writing data through a service layer (be it WCF or normal web service). Then this service layer will do one of two things: 1. write data to database 2. and/or trigger the background process by placing a message in the queue. 3. obviously it can also retrieve data from database. The little agent (a windows service) on the other side of the queue will monitor the queue and execute based on the task command.
This architecture will be quite easy to scale (add more queues and agents) and easy to implement compared to RPC or distributed execution or whatever. And the agent processing doesn’t need to be real time. And the agent and service layer are separate applications except they share the common domain objects and Repositories etc.
What do you think? Architecture suggestions for the above requirements are welcomed. Thank you!
WCF adds an abstraction over MSMQ. In fact, once you define compatible contracts (operations must be OneWay), you can switch out MSMQ in the config, transparently. (For instance, you could switch to normal HttpWS or a NetTcp binding.)
You should evaluate the other WCF benefits, like security and so on, to see how those fit in with your needs. Again, they should be reasonably transparent of the fact you're using MSMQ underneath. For instance, adding SOAP security and so on should "just work", independent of using MSMQ.
(Although, IIRC, you still need to login to the desktop on each machine that uses MSMQ, with the service account that will use MSMQ, to generate the certificate in the machines local profile. And then, it doesn't work very well from IIS6, since user profiles aren't loaded. A real pain in general, but nothing to do with WCF specifically.)
Apart from that:
Have you looked at SQL Server Service Broker? After using MSMQ + WCF and SSSB, I think that SSSB is vastly easier to configure and manage. SSSB works with T-SQL commands over any SQL client (I use it from Mono, on Linux, with transactions). It'll also give you transactional send/receive, even remotely (I think MSMQ 4 now allows this). It really takes a lot of the pain away from message queuing, and if you're using SQL Server already...
SSSB is often overlooked since the SQL Management Studio doesn't have GUI designers for it all, but it isn't hard and is a great option. The one downside is that if you want local send capability (i.e., queue message when network is down), you'll need to run a local SQL Express instance.
Your architecture seems sound and reasonable. However you should consider using the WCF net MSMQ transport over hand coded MSMQ classes. WCF wraps this common functionality into a nice programming model. Also I believe there is some improvements in the protocol used by wcf compared to basic System.Messaging
Have a look at the value-add over plain MSMQ:
http://readthedocs.org/docs/masstransit/en/latest/overview/valueadd.html
In summary, you get a lot of messaging concepts clearly presented in the API with MassTransit; to an extent you wouldn't have if you hand-coded it or used WCF.