Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [high-availability]

High-availability technologies mask the effects of hardware or software failure, so that perceived downtime for users and applications is minimized.

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PostgreSQL High Availability/Scalability using HAProxy and PGBouncer

I have multiple PostgreSQL servers for a web application. Typically one master and multiple slaves in hot standby mode (asynchronous streaming replication). I use PGBouncer for connection pooling: one instance installed on each PG server (port 6432)…
Nicolas Payart
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What is the modern way to partition PostgreSQL across machines, when the data is "naturally partitionable"

After several years of dwelling into the "NoSQL" space, now I have a problem that is quite "relational" in its nature. Today I see data stores with quite different eyes than before. Things like Riak have spoiled me in a way that I can no more…
loxs
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Is there a complete list of Online operations for each SQL Server version?

As we are about to change some of the large tables in our 5TB database I found myself needing a list of the operations that can be performed online and the which require full locks to be held while they run. Ideally, this list would also contain…
Thomas Kejser
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SQL Server Database Mirroring is going to die. How can I guarantee high availability now?

The Database Mirroring feature of SQL Server is going to die: This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this…
John Assymptoth
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Do schema changes "break" Availability Groups or are they handled transparently?

My organization is planning to adopt SQL Server 2012 Availability Groups and I am trying to understand what impact (if any) it will have on our application upgrade process. We release application updates on an 8 week cycle and any release could…
Matt O'Brien
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SQL Server equivalent to functionality of Oracle RAC?

I did some Googling and couldn't find an answer to this question more recent than a few years ago, so I thought I'd ask. Oracle's RAC feature offers load-balancing for both read and write transactions, as well as scale-out and high-availability…
SqlRyan
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What reason could cause AWS RDS connections to spike

It's my first time using RDS on AWS, I use a t2.medium instance running MySQL Aurora with default configs. The CPU usage and DB connections is quite normal until "something" happens, which causes the DB connections go all the way up to its maximum…
TrungDQ
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What are the differences between Mirroring and Failover Clustering and when is each one recommended over the other?

What are the main differences between Mirroring and Failover Clustering? What kind of problem each one solves and in what kind of scenarios is each one recommended over the other?
ivanmp
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SQL Server AlwaysOn to run updates and schema changes in 24/7 environment

First of all i have to say that this question comes from a software engineer-perspective. Unfortunately we have no DBA so we need to administer our own databases. We have SQL Server 2012 Enterprise installed to run a database which should be…
Jeroen1984
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High Availability for postgresql

I'm new in PostgreSQL database. Recently our developer needed to do some upgrades in our systems. Because of that we are planning to implement some method in order to implement database failover. Based on my reading from postgresql wiki here, we are…
user119720
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What is the best option for High availability on a data warehouse?

I have a customer who have an existing 1.5Tb data warehouse and are currently planning for a complete refresh of the DW on a new environment. Their infrastructure manager has organised 2 servers with SQL 2017 standard on each and has now asked me to…
Nick Baker
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Can Availability Groups replace transactional replication?

I've been looking at the new features of SQL Server 2012, and how it can help my current situation. Currently we're on SQL Server 2008 R2, and replicate two OLTP servers' databases to a single reporting server via transactional replication. We then…
Meff
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Does "Synchronous-Commit Availability Mode" ensure consistency between Replicas?

If one refers to the MSDN documentation, on Synchronous-Commit Availability Mode, you may read: Under synchronous-commit availability mode (synchronous-commit mode), after being joined to an availability group, a secondary database catches up…
Jodrell
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SQL Server replication for off site copy

We have our Primary SQL Servers in-house (15 primary servers at the moment (500 databases approx overall), most of the servers have hex core processors). These are mirrored to other backup servers in a near-by building (via a dedicated 0ms fibre…
HeavenCore
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Recovery time effects of Availability Groups

We did different kinds of basic Tests and AlwaysOn passed in many tests. We finally did a heavy write test for AlwaysOn and it gave surprising results. The actual Test details are here, the goal is to see if AlwaysOn availability group can…
WrinkleFree
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