master-slave

using WCF as a master-slave command model.

I'm developing a master-slave command model by which some application "Master" sends commands to homogenous processes called "Slave" to do some task and then respond back with status complete or process failure. they should also expose some data to the master available on request. What would this model look like in WCF? would Master a...

mysql slave database problem

Currently we have 3 slave databases, but almost always there is one of them extremly slow than others(can be an hour after master database) Has any one met similar problem?What may be the cause? ...

What's the best way to create a master-slave configuration for a web app?

I'm creating a server management interface for a few of my servers (which host virtual servers) and I wanted to know the best way to implement a master-slave configuration for said interface. The master server should connect to all the slave servers in order to retrieve information (provide a high level overview) and send them commands ...

How to validate selects / inserts are hitting the right server with MySQL Master/Slave

I've got a rails app using the master_slave_adapter plugin (http://github.com/mauricio/master_slave_adapter/tree/master) to send all selects to a slave, and all other statements to the master. Replication is setup using Mysql master / slave. I'm trying to validate that all the SQL statements are indeed going to the right place. Select...

Ruby On Rails Master-Slave Postrgres Databases

I am currently setting up a master-slave app using Ruby on Rails that needs to have a Master-Slave backend. I'm currently looking at using Slony for the replication component, and Masochism for handling the read/write connections to the different DBs. This is my first time setting up master-slave DBs with Ruby on Rails, and these are t...

How to write the Mysql binary log position of master when doing a mysqldump from slave?

I am currently running mysqldump on a Mysql slave to backup our database. This has worked fine for backing up our data itself, but what I would like to supplement it with is the binary log position of the master that corresponds with the data generated by the mysqldump. Doing this would allow us to restore our slave (or setup new slave...

ActiveRecord counter_cache giving stale count with multi_db gem

I'm using the multi-db gem with Slony-I replication on PostgreSQL in a Rails app. This mostly works perfectly, but there is a bit of a replication lag in certain cases. One of the cases involves an ActiveRecord counter_cache. For clarity, assume the following two models: class Post < ActiveRecord::Base has_many :comments ... end c...

Master / Slave switch in the Zend Framework application layer

I am writing an application which requires the Master/Slave switch to happen inside the application layer. As it is right now, I instantiate a Zend_Db_Table object on creation of the mapper, and then setDefaultAdapter to the slave. Now inside of the base mapper classe, I have the following method: public function useWriteAdapter() { ...

How to start Camel routes on slave ActiveMQ only when slave becomes active in failover?

I have a durable consumer to a remote JMS queue in embedded Camel routing. Is it possible to have this kind of routing with master-slave configuration? Now it seems that the Camel routes are started and activated already when slave ActiveMQ is started and not when the actual failover happens. Now it causes the slave instance to receive ...

Java me : Can we retrieve bluetooth address of connected device from an open slave connection ?

Here is a typical sequence of events that occur : Host device opens a service ( Host device accepts and opens all incoming connections) A remote device connects to host device. Now, we have a slave connection open at host device. At host device, I want to know the bluetooth address of remote device. I can always pass it as data from ...

Autoscaling mysql on ec2

Hi I need autoscaling of mysql-slave on ec2 can anybody guide me how to do that and how to transfer the load on newly added instance ...

What's a good Java-based Master-Slave communication mechanism?

I'm creating a Java application that requires master-slave communication between JVMs, possibly residing on the same physical machine. There will be a "master" server running inside a JEE application server (i.e. JBoss) that will have "slave" clients connect to it and dynamically register itself for communication (that is the master wil...

Surgical slave reads for Ruby on Rails, mulitple databases.

Greetings, I'm currently working on a multiple database rails application. I want to off load the SELECT queries on to the slave databases for only SOME of the databases or specific models. The issue is that in places, we swap out the current database connection and put in a different one for a short time; to load fixtures or to hand...

Changing postgres user password in a master-slave setup

We have PITR setup and WAL shipping enabled. We would like to change the password for the user postgres. The process is simple enough. However, since we cannot connect to the SLAVE how would we make sure all passwords are in synch? Would temporarily disabling WAL shipping allow me to connect to the slave to change the password there? I c...

Restarting postgres DB servers in a master-slave setup

Is there any documentation on gracefully restarting servers that have PITR implemented. We have a master-slave setup. I want to make sure servers are rebooted in the correct order so as not to mess up WAL shipping. Should i disable WAL shipping prior to server restart? ...

Scalability design question - master/slave databases

Hi! I just finished a database layer based on redis that offers to select between multiple databases, but I have no experience by myself on what should be common sense to do. Reliability is my biggest focus. How is writes and reads commonly organised in applications where both a slave and a master database is available? How do the big...

DelayedJob and `master_slave_adapter`; losing the master connection

We have a Rails application that is running in a MySQL master-slave set-up for a while now, using the master_slave_adapter plugin. Recently, there was a need for background processing of long running tasks. So we settled on DelayedJob. DelayedJob's table/model uses the same master-slave adapter. And it keeps the slave connection alive b...

How to reset(?) a (out-of-sync)DB on a MySQL master-master replication

I have a master-master MySQL replication. It was delicious until yesterday but, for some reason which I could not figure it out yet, they lost synchronization. I've been wandering around forums and several tools, tips and advices but it seems like I cannot not figure it out myself in time. So I have the idea just to reset the problemati...

hudson and vmware player or virtual box, windows slave

I am currently running ubuntu 10.4, I would like to be able to run windows XP from within that machine, using vmware player/workstation. I am not sure which is better for my situation. I need to verify my builds under a windows environment, which is why i need the vmware software, Does anyone have experience, running Hudson slaves on wi...

Hudson -- Dumb slave

I have been playing with Hudson slaves lately, I was wondering what a dumb slave is? and when is it beneficial to use? An example would be nice. They suggest there are other types of slaves but they then again list none. Thanks ...