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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19
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2answers
4k views

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 ...
18
votes
2answers
490 views

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 ...
10
votes
5answers
11k views

SQL Server equivalent to functionality of Oracle RAC? [closed]

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 ...
8
votes
2answers
11k views

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?
8
votes
2answers
792 views

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. ...
8
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1answer
2k views

Do schema changes “break” SQL Server 2012 AlwaysOn or are they handled transparently?

My organization is planning to adopt SQL Server 2012 AlwaysOn and I am trying to understand what impact (if any) it will have on our application upgrade process. We release application updates on an ...
7
votes
2answers
1k views

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 ...
6
votes
2answers
9k views

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: ...
6
votes
1answer
1k views

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 ...
6
votes
1answer
137 views

Where to put a database in case of IP failover?

I understand that to achieve some level of availability of an online application it is possible to organize an environment with a redundancy using an IP failover mechanism and switching between ...
5
votes
2answers
2k views

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 ...
5
votes
2answers
437 views

Replication with FileStream

I need to setup database replication (for high availability) on a database that uses FileStream. This is on SQL Server 2012 Standard Edition, so Always On or Peer-to-Peer replication is not an option. ...
5
votes
2answers
3k views

Recommended distributor architecture for transactional replication?

We are planning to create a Transactional replication on 2 nodes of SQL Server 2008 R2, each node will be a publisher and a subscriber. What is the best practice in order to have this scenario done? ...
5
votes
0answers
93 views

Low performance, high availability, replicated key/value store with audit trail

I'm looking for a database system with fairly specific specs. I've looked most of the major relational databases and NoSQL products out there and did not find one that even remotely satisfied my ...
4
votes
1answer
677 views

SQL Server 2012 - Always On

I am in the process of setting up always on high availability clusters for the first time. Can anyone explain to me from the networking perspective after configuring the group and testing to make sure ...
4
votes
5answers
2k views

Setting up a Redundant Sql Server 2008 Configuration While Retaining High Performance and Minimal Downtime

We have a situation where we are moving to a new hosting facility and are attempting to configure our new database environment. However, none of us are formal DBA's so a lot of what we are doing is ...
4
votes
1answer
6k views

Restoring a SQL Server 2012 database in high availability

I have a database which is in always-on high availability mode synchronized with another database on a different instance. How can I restore from a .bak file into the primary database using T-SQL? ...
4
votes
1answer
515 views

SQL Server DR, mirroring or virtualise and mirror

I have a client with a small business server 2008 Premium installation. This obviously includes SQL Server 2008 standard on a separate 2008 server. On the SQL we run several line of business ...
4
votes
1answer
4k views

MySQL Replication and High Availability

I know this might not be a very good question to be asked in this site, but I really need some helps/hints to be directed to the right path. I want to have failover strategy for 2 MySQL servers which ...
4
votes
2answers
572 views

Is MySQL Clustering a viable option for a DB expecting 5TB of data in 5 years?

We plan to implement MySQL Clustering.The database should support 5 years of data and expected data/year is 1TB. When we created a test enviornment with the DB size as 200GB, NDB Cluster took more ...
4
votes
1answer
1k views

Transaction Log Truncation with Copy Only

I have a database backup job set to use full backup with the Copy only option on once daily. The copy only is on because from what I have read that is the only way to backup a database that is ...
4
votes
2answers
4k views

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 ...
4
votes
0answers
208 views

ENABLE_BROKER vs NORECOVERY

I have two nodes with MSSQL2012 which work with AlwaysOn High Availability After some crash I had to remove db from availability group on the one of the nodes. For restoration I've made backup ...
3
votes
1answer
1k views

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 ...
3
votes
1answer
518 views

Three Node Cluster that Allows For Two Failures

We are creating a three-node three-instance cluster with SQL 2008 R2 (not cutting edge, but that is what the application supports) and think it should be able to maintain quorum with two physical ...
3
votes
1answer
125 views

Effects of turning the transaction safety OFF

I am considering to turn off the transaction safety to maximize the performance. Before that i am interested in finding the current status of transaction safety. Is there any command that we can get ...
3
votes
1answer
787 views

timeline 2 of the primary does not match recovery target timeline 1

I want to create a configuration with postgresql and pgpool to get height availability (HA). I want to do this: .-----. .--------. | | W | DB | | APP ...
3
votes
1answer
704 views

Failover Cluster Diagnostic Logs

I know there must be a simple answer to this question, but I cannot find it anywhere. Our SQL 2012 FCI have SQLDIAG .XEL files in their MSSQL\LOG folder. In some instances, these files are often ...
3
votes
4answers
2k views

MySQL cluster - how many hosts are needed for full HA?

I need some clarification on MySQL-Cluster (NDB) setup I want to achieve full HA but I'm low on server budget and can't afford to rent a dozen of servers for simple solution that I'm working on. ...
3
votes
1answer
1k views

Failover Cluster and AlwaysOn Availability Groups across Data Centers

We have two 3 node clusters in separate data centers, let's call them ClusterP and ClusterS. ClusterP is our primary and ClusterS is our secondary for disaster recovery. Each cluster has multiple ...
3
votes
1answer
1k views

Availability mode - manual failover mode, best practice for availability mode?

We don't want automatic failover for our availability group, but I have set availability mode to Synchronous, was that a mistake? The availability group runs on vmware with windows 2012R2, and I got ...
3
votes
2answers
3k views

SQL Server 2012 High Availability on VMware virtualization

We're going to host a large SQL Server 2012 under a VMware virtualization and we need it to be highly available. These are the three options I found supported, but couldn't find a lot of info and ...
3
votes
2answers
754 views

Best high availability solution to avoid maintenance downtime?

We currently only have one production SQL Server 2008 server. Anytime we need to perform maintenance or install patches, it causes downtime as the server reboots. In addition, if the server ever ...
3
votes
1answer
36 views

High availability on a subset of the data

On my site, I have a set of big databases (+6TB total) that is running on a SQL Server 2012 instance. One of these is the main DB and the other ones are archived data that are queried sometimes ...
3
votes
1answer
2k views

MySQL: Alter Table on very active table gives “Waiting for table metadata lock”

At my work, we've recently upgraded to MySQL 5.5 and since then, have been bitten a few times by the new (and intended) behavior of metadata locking. Basically, whenever we run an ALTER TABLE ...
3
votes
1answer
6k views

Do Availability Groups support Active/Passive? [closed]

I am looking into the licensing of SQL Server 2012 when using Availability Groups with 2 servers. It is not clear to me if Availability Groups are only available as Active/Active and not ...
3
votes
1answer
1k views

Robust Mysql failover using free tools [closed]

I am looking for a free solution to set up Mysql in an active/passive configuration, in order to provide high-availability. In particular, a Bugzilla installation, and MediaWiki needs to stay alive ...
3
votes
1answer
193 views

Which database?

We have to launch a new service in my company with a big database. And I currently don't have that much knowledge. We did a small preview of the service and our biggest table had more than 2 100 000 ...
3
votes
1answer
2k views

Mirroring not working after a server crash

I'm using SQL Server 2008R2. Last night, the host machine on which my mirror database was running basically went belly up. Thankfully the principle database was on a different host server and so was ...
3
votes
2answers
85 views

SQL SERVER 2014 Standard - High Availability Listener solution

The company has SQL Server 2014 Standard licenses and we're standing the servers up in a VMware environment. My initial plan is to create 2 instances on each DB server and run Instance1 on SQL1 as ...
3
votes
2answers
333 views

Change SQL Server 2000 from Active/Active to Active/Passive

I know it's cringe-worthy to use this term, but I have a SQL Server 2000 cluster with one clusetered instance running on it with multiple resources running on one of the two servers in the cluster all ...
3
votes
1answer
864 views

AG and SQL Backups

I am using always on in sql 2012 and have an AG setup. I would like to know if i were to backup the primary database and restore it would that be allowed without taking the cluster down etc. ...
3
votes
1answer
2k views

Configured MySQL replication but its not working

I have configured MySQL master and slave replication setup on 5.5.x. But for some reason data is not getting replicated properly. What might be the reason? At Master: /etc/my.cnf [mysqld] ...
3
votes
1answer
62 views

SQL Server - Company wants HA for single instance with 1 userDB - sanity check and questions

I am new to SQL Server (2 months) and learning at a gov company (europe). The job is to make a HA solution for this 1 productive instance (1 database). Following is given SQL Server 2012 Windows ...
3
votes
1answer
3k views

PgPool 2 with HA Proxy

So, I'm looking to add high availability to a postgresql server. I've looked into some tutorials on the web but, haven't been able to find exactly what I'm looking for. E.g.: PostgreSQL ...
3
votes
1answer
2k views

Removing secondary replica from SQL Availability Group causes large log file

Due to an unforeseen hardware error, I had to take our secondary replicas down for maintenance. This was really due to a storage issue and, it was decided at a higher level, to purchase a new storage ...
3
votes
0answers
871 views

SQL Server Database Mirroring : strange client application behavior upon failover

I am putting a HA SQL server environment up based on three SQL Server 2008 R2 machines and database mirroring. I'll name them : principal.company.intra mirror.company.intra witness.company.intra ...
2
votes
3answers
1k views

How to check history of primary node in AlwaysOn HA environment?

How do I see history of failovers of the primary node in cluster? I'm trying to figure out at what point secondary node started to act as primary. We are running Windows Server 2012 with SQL Server ...
2
votes
1answer
455 views

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 ...
2
votes
2answers
855 views

Oracle symmetrical one-way replication for cheap HA: unfashionable or technically unfeasible?

We have two smallish unrelated databases on two big Oracle Enterprise servers. Instead of buying more licenses and servers for high-availability replicas, can we replicate database B to server A and ...