database-replication

I have 12 databases totaling roughly 1.0TB, each on a different physical server running SQL 2005 Enterprise - all with the same exact schema. I need to offload this data into a separate single database so that we can use for other purposes (reporting, web services, ect) with a maximum of 1 hour latency. It should also be noted that these servers are all in the same rack, connected by gigabit connections and that the inserts to the databases are minimal (Avg. 2500 records/hour). The current method is very flakey: The data is currently being replicated (SQL Server Transactional Replication) from

I have one Redis instance that has two databases. Now I want to set up a second instance and replicate the first instance, but the second instance should only have one database and replicate only db 0 from the first instance. When I try to do it (set slaveof ... for the second instance) I get the following error message in the Redis log file: FATAL: Data file was created with a Redis server configured to handle more than 1 databases. Exiting I tried using redis-dump but I get an error when I try to import the generated dump into the new instance. (not related to 2 dbs vs. 1 db I think, rather

I am new to Cassandra was going though this Article explaining sharding and replication and I am stuck at a point that is - I have a cluster with 6 Cassandra nodes configured at my local machine. I create a new keyspace "TestKeySpace" with replication factor as 6 and a table in keyspace "employee" and primary key is auto-increment-number named RID. I am not able to understand how this data will be partitioned and replicated. What I want to know is since I am keeping my replication factor to be 6, and data will be distributed on multiple nodes, then will each node will be having exactly same

From my understanding from the below questions which were asked quite some time back, Redis doesn't have a built-in support for master-master replication. Question 1 Question 2 Question 3 The official website as of now looks like there is nothing much to it about master-master replication. Is this still the case, i.e., does Redis still have no options for multi-master replication. And even third-party tools don't seem to be helping Redis achieve the same. I came accross Zabcluster and Zookeeper but I'm not sure if this would meet my requirement of a simple master-master setup without much

We have a setup of two mongodb shards. Each shard contains a master, a slave, a 24h slave delay slave and an arbiter. However the balancer fails to migrate any shards waiting for the delayed slave to migrate. I have tried setting _secondaryThrottle to false in the balancer config, but I still have the issue. It seems the migration goes on for a day and then fails (A ton of waiting for slave messages in the logs). Eventually it gives up and starts a new migration. The message says waiting for 3 slaves, but the delay slave is hidden and prio 0 so it should wait for that one. And if the

I'm testing this great gem Octopus with Rails 4.0.2 in development. I created a Slave db and configured octopus as follows (config>shards.yml) : octopus: environments: - development replicated: true fully_replicated: true verify_connection: true development: slave1: host: 192.168.1.12 adapter: mysql2 username: slave_reader password: my_password database: my_server_development reconnect: true It works very nice, reading from the Slave and writing to the Master, however if My Slave server is down, I would expect it to redirect to the Master db and get the content, but after some time trying, it

PostgreSQL 9.4 introduced Logical Decoding: http://www.postgresql.org/docs/9.4/static/logicaldecoding.html It also has Cascade Streaming Replication: http://www.postgresql.org/docs/9.4/static/warm-standby.html#CASCADING-REPLICATION Logical Decoding seems to be based on Streaming Replication. However a PostgreSQL server will refuse to start a Logical replication slot on a hot standby. It will only allow Logical Decoding on the master node. What prevents a hot standby node to replicate itself in cascade using Logical Decoding? A patch was submitted for PostgreSQL 10, but didn't get in . Work

Lets say I have a datbase of Cars. I have Makes and Models (FK to Makes). I plan on having users track their cars. each Car has a FK to Model. Now, I have a lot of users, and I want to split up my database to distribute load. The Makes and Models tables don't change so much, but they need to be shared across shards. My thought is to use MySQL replication from a master DB of makes and models to each slave database. My question is: Can I safely write to the slave databases assuming I don't write to those tables on the master? And while on the subject, is there anyway to guarantee one slave