I have two servers.i Want to setup Replication( Transactional publication ) between the two servers.The servers are on different domain.
After Going through the configuration for Distributor,Publisher and Subscriber.
I View the Syncronization status and start the snapshot agent.
It ran up to 100% and then stop.I click on the monitor replication button and ViewDetails,it Show this error messages:
The process could not connect to Subscriber 'Mydomain\myusername'. (Source: MSSQL_REPL, Error number: MSSQL_REPL20084)
Viewing the Syncronization on the subcriber display another error
It says:
The process could not connect to Subscriber 'mydomain\username'.
Could it be that replication cannot be setup on databases on two different domain?
It is likely the replication agent process account does not have the required permissions and/or you are trying to replicate across untrusted domains.
Replication across non-trusted domains or workgroups can be done using Windows Authentication by configuring pass-through authentication.
Create a local Windows account on both the Publisher and Subscriber that has the same username and password. Use this account for the replication agent process account and have the connections to the publisher, distributor, and/or subscriber impersonate this account. Ensure the account has the permissions required in Replication Agent Security Model.
This approach is covered in the section Use Windows Authentication to Set Up Replication Between Two Computers Running SQL Server in Non-Trusted Domains in HOW TO: Replicate Between Computers Running SQL Server in Non-Trusted Domains or Across the Internet.
Related
I'm trying to build a simple chat with websockets. I'm also displaying the current active users in the chat, and here is where the problems start: we use a web farm.
A user can connect through a loadbalancer with a server. When a new connection hits a server, it increases a counter in a SQL database and notifies the other servers in the farm through rabbit MQ.
All other servers fetch the new data and send that number back to their connected users.
If an user disconnects, the same will happen: The server decreases the counter in the SQL database and through rabbit MQ all other servers will know about this.
But, what will happen when a server dies? for example, If 10 users will be connected with this server. When that server goes down, all the users are disconnected, but that is not updated in the database anymore.
What's the best solution to get the total amount of active users in a web farm? And notifying the users when this amount has changed?
Thanks in advance!
Oh btw, we're using signalr
I think the typical way to deal with nodes asynchronously disconnecting from a mesh is to implement a heartbeat/keep-alive mechanism. In this case the heartbeat message would be between servers and there must also be an accessible record of which users are connected to which server. When a server does not produce a heartbeat for a period of time, then all other servers can update their records and mark all the users associated with the server as disconnected.
Looks like you may have a few options on how to keep track of users (SQL database or every server listens a Rabbit MQ message). As far as the heartbeat, you can implement it yourself or try to see if the laodbalancer's detection method can be utilized.
I would really appreciated another perspective on an issue we have been experiencing.
The environment:
We have a small subset of VMs (5 Windows Server 2008 R2 VM's) hosted on a Windows Server 2012 Cluster of 8 Physical Hosts which supports 100's over VMs across various OS (2008/2012 etc).
The issue:
Servers within the subset of VMs experience widespread network SERVICE failures. The failure presents itself as a loss in connectivity for a large number of network related services operating on the VMs (including certain critical network dependant applications).
The impacts:
Server remains online.
Inability to RDP to the servers via Domain Accounts (Local accounts are fine).
Windows event logs associated with Netlogon Failure: Event ID 5719 - This computer was not able to set up a secure session with a domain controller in domain DOWNERGROUP due to the following:
The RPC server is unavailable. This may lead to authentication problems.
Windows event logs assocaited with Group Policy Failure:
Event ID 1054:The processing of Group Policy failed. Windows could not
obtain the name of a domain controller. This could be caused by a name
resolution failure. Verify your Domain Name System (DNS) is configured
and working correctly
Widespread Agent Failure (AV, Monitoring, Application) - Lack of connectivty to centralised management servers.
The resolution(s). Stopping an agent service. Strange however its not limited to a specific agent however if we stop agent A, the server comes back to life, however if we also stop agent B, the server comes back to life with Agent A still running. Restarting the VM also resolves the issue.
Note that these events do not appear on other VMs hosted off the same host at the time of the outage. Also note that the guest is located on the same host prior to, during and after the outage.
We have investigated the suspicion that their may be issues with Dynamic Range Port Allocation with the server possibly getting into a bottleneck state. We have implementedthe "MaxUserPort" and "TCPTimedWaitDelay" registry parameters and have set them to 65k and 30 respectively.
Also note that when an outage occurs, it does not always occur on the same VMs in the group. Often times it is 2, 3, 4 or all servers.
Im really just asking if anyone can see these symptoms and relate to possible causes for our situation.
Any help/discussion would be appreciated.
Well, this turned out to be an interesting resolution.
We discovered that one of our server agents, while not actually showing open ports in Netstat, had over 40,000 handles growing linearly over time.
Had to enable the "handles" column in task manager to be able to see this info.
This was the miracle post...
http://blogs.technet.com/b/kimberj/archive/2012/07/06/sever-quot-hangs-quot-and-ephemeral-port-exhaustion-issues.aspx
My project supports nested transactions and thus we have MSDTC service running on web server as well as on database server. The project is working fine. However, we have database mirroring established over database server and thus whenever fail-over happens, site page where, nested transactions are used, throws an error:
The operation is not valid for the state of the transaction.
We have MSTDC service running on mirroring database too. Please suggest what should be done to overcome this problem.
In the default DTC setup it is the DTC of the server that initiates the transactions (the web server in your case) that coordinates them. When the first database server goes down, it rollbacks its current transaction and notifies the transaction coordinator of this and that is why you get the error. The webserver cannot commit the transaction because at least one participant has voted for a rollback.
I don't think you can get around that. What your webserver should do is retry the complete transaction. Database calls would than be handled by the mirror server and would succeed.
That is at least my opinion. I'm no authority on distributed transactions, nor on database clusters with automatic failover...
LDAP Fault-tolerance configuration (e.g SunOne):
Does anyboby know how to configuration "Fault-tolerance" for LDAP, e.g SunOne LDAP.
I search via google without any userful result?
Thanks
Assuming, by "fault tolerance," "high availability (HA)" is being asked, I would say it can be achieved by redundancy. And, it would not be peculiar to SunOne or any directory server software from other vendors.
There are different ways to solve this. It depends on the business requirements and the affordability. One method that comes to mind is to have the LDAP software installed on an HA pair. This requires hardware and OS capabilities for fail-over and it requires two servers (in a world of virtualization, "server" can mean different things [physical box, frame, LPAR, etc.]; so, I'll just leave the interpretation to the reader). When one server fails, the other server takes over and assumes the primary role in the pair. This is the fault-tolerance part. In this approach, the machine/server with the secondary role is passive (i.e., it's not serving clients) until the primary goes down. You will need to implement LDAP data replication between two servers. They can be two LDAP masters in a P2P replication topology.
Another method is to have multiple LDAP servers (i.e., masters, replicas) and cluster them using a network dispatcher (ND) software/appliance/etc., which would distribute the incoming traffic to the individual servers (usually replicas) in the cluster. If you lose one replica in the cluster, ND will not send any traffic to that replica until it comes back. However, other replicas will still be receiving load and therefore serving to the incoming traffic. This is the fault-tolerance part in this method. The degree of the availability you want will also dictate what can be done in a clustered environment. You can have a single LDAP master (to which the organization's applications would make updates) and keep it out of the cluster, but pair with another server for fail-over (so you wouldn't lose availability for updates from the applications - this also gives you the freedom to do maintenance on the master without interrupting your applications [well, they need to be written to be able to write to more than one LDAP master if the primary one is not available]). You would have to have the secondary server to receive replication from the primary in any case. If the budget doesn't let you have more servers/replicas, then you can put the master server along with replicas in the cluster as well to help with the read traffic. Instead of an HA-pair in which one of the servers would be passive, you can have two masters configured in a P2P replication topology and have them both in the cluster to help with the traffic too. There are different ways to approach to this method depending on the level of redundancy wanted or that can be afforded.
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.