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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One name for use in a connection string

I'm not primarily a dba so I apologize if this question is high-level and please provide feedback if I'm asking the wrong question or going about this the incorrect way. I currently have one ...
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1answer
1k views

Add shared folder to AlwaysOn AG Failover

We have setup a 2 node Synchronous AG with automatic failover to provide HA for our ERP application (Dynamics GP) The GP desktop client loads a number of shared reports and dictionaries from a file ...
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JDBC Connection on Current Primary Database After Switchover: ORA-01033 encountered

We are using Oracle Data Guard and currently testing Disaster Recovery scenarios, which is starting the application after switching over from the Primary Database to the Secondary Database. I am ...
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1answer
330 views

What sequence when changing the master MySQL server, but not IP?

I change the replica to the master server. But the IP master remains the same. * The second replica itself will continue to work, without changing the settings? * On the old master, just change ...
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3answers
4k views

Primary and secondary replicas on same server

We're considering different options for HA/DR with SQL Server 2016. AlwaysOn Availability Groups are obviously an option. I understand we can read from secondary replicas, unlike DB mirroring for ...
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0answers
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Copy un-replicated Bin logs from Master to Slave , if Master goes down MySQL 5.7 Enterprise

I have async-Classic file based replication with 2 Nodes as Active - Active. R/W is happening on Primary Node (PN) only and Secondary Node (SN) has been setup as HA only. SN has been configured as ...
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0answers
52 views

Unexplained connections from one SQL server to another

I just installed 2 SQL Server 2016 Enterprise and configured a High Availabilty Group. As a test object for the HA-Group I used a database I restored from another server. It's a database called "...
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1answer
77 views

How come website be random slow? Open sleep processes?

My website is randomly very slow by high MYSQL CPU, and I have no idea what the problem is. Hopefully I will come closer to the solution with this post. If I check the mysql processes, I see a lot of ...
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1answer
921 views

Sync data near real time between 2 databases on 2 different servers

One of my clients asked me to find a solution that can sync the 2 databases in near real time. Basically, they try to pull the data through linked server from server A through server B, but since ...
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0answers
348 views

MySQL 5.7 Replication failover in Master-Master configuration in RHEL

Asynchronous Replication Scenario ( Binary Logging Method) : Primary Node <-----> Secondary Node Write is enabled on Primary node and Read is enabled on both ...
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1answer
1k views

Replication on Always On

I have two SQL Servers 2014 Enterprise Edition (SERVER A, and SERVER B) designed for Always On Availability Group. There are 5 databases in the AG. I have been told that we need to replicate one of ...
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2answers
2k views

SQL Server high availability fn_hadr_backup_is_preferred_replica returns 0 zero on secondary

I'm running the Ola Hallengren Maintenance Solution and noticed the transaction logs weren't being backed up on the secondary, hence not being truncated, despite the AG backup preference being set to ...
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1answer
910 views

SSIS with MultiSubnet Availability Groups

I am planning for a "multi-subnet" AG group . 2 at the primary data center in DC and one at San Jose. We are planning to test a vendor application which requires SSIS. I am planning for the SSIS to ...
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1answer
1k views

Powershell SQL Server High Availability PrimaryReplicaServerName - inconsistent results

I developed a simple PowerShell script to list which High Availability replica is the current Primary. Seemed to work. Did a manual failover to test it, but results become inconsistent, often ...
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1answer
246 views

Automatic MYSQL failover

We have a wordpress environment however this is not a wordpress question. Our scenario is that front Ends connect to a MYSQL backend (MYSQL VM1) which is replicated to a backup vm (MYSQL VM2). The ...
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2answers
2k views

SQL Server 2016 - Mirroring

Im a complete beginner with SQL server. I'm trying to train myself using the AdventureWorks2016 sample DB on an SQL server 2016. I'm trying to setup mirroring between VM1/SQLServerInstance1 and VM2/...
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0answers
94 views

SQL Server 2016 HA Options for thousand databases

Currently we have a 4 node Active\Active\Active\Active Windows\SQL Server 2008r2(ENT Edition) cluster that we need to upgrade to Win2012r2\SQL Server 2016. We have over a thousand databases, and ...
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1answer
321 views

azure sql failover duration

I have a azure sql database in North Europe Region. It is almost 5 MB and it has Basic Pricing Tier. That database is not in Azure VM. I am using PaaS environment. I configured Geo-Replication ...
3
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1answer
550 views

High availability SQL Server without Active Directory

I'm fairly new to SQL Server. I'm looking to achieve a highly available SQL Server setup where if the primary database fails, the backup database takes over. What would you guys recommend? I'm ...
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3answers
2k views

MySQL H.A with automatic failover

MySQL has a lot of different highly available solutions, I would like to know what are the differences between all the current implementations, here are the implementations that look currently up to ...
3
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1answer
900 views

SQL Server High Availability without Windows Clustering

As per my understanding and information, there isn't any SQL Server High Availability(HA) feature without Windows Server Failover Clustering mechanism (WSFC) being used. SQL Server Mirroring used to ...
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1answer
3k views

MySQL 5.7 group replication disables access over TCP/IP

I'am testing new group-replication feature on MySQL 5.7 with multi-master replication on a Windows 2012 R2 system. I'm using for testing a single server and install to MySQL instance onm TCP-Ports ...
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0answers
248 views

AlwaysOn Availability Group and workgroup servers

Has anyone had any luck setting up AGs with servers in a workgroup, neither server in a domain (no domain even exists for this client). I've added DNS suffix to both servers, like recommended. I have ...
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3answers
2k views

SQL Server Always On Node and File Share Majority

I am looking for some guidance on architecting our SQL Server 2016 SP1 Always On Availability Groups HADR solution on Windows Server 2012 R2. We have a primary site A with a primary replica and a ...
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2answers
968 views

How can MongoDB elect a new primary when a datacenter has failed?

I am curious about the following situation when setting up a MongoDB cluster. 2 Datacenters, 2 nodes in each data center for a total of a 4 node replicaset. One of the two datacenters has become ...
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1answer
511 views

Automatic Failover or Database Mirroring?

We have a software backed with database. We want to keep database at a remote location and have it all the time available. For this task, a 5 year old project experience came into my mind. I remember, ...
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0answers
98 views

Mysterious alwaysOn breakage on SQL Server 2012

I've just bumped into a new situation regarding alwaysOn availability. We have a setup with a large database (terabyte range) with one primary and one secondary replica. Geographically the servers are ...
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2answers
661 views

High availability database switchover

I have a database in a high availability group with two nodes and one listener. Several times a week, I have a problem with switchovers. The message I get is: Stopped listening on virtual network ...
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2answers
3k views

PGPool II - Failover when current master node dies

I have a 2 node high-availability postgresql 9.5 cluster. I'm using streaming replication, PGPool II (3.5.4 [ekieboshi]), and a virtual (or floating) secondary IP all hosted on aws to accomplish this. ...
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0answers
61 views

Losing records during transitioning to a failover cluster

Recently we had an outage in our primary SQL Server cluster and traffic was directed to the fail-over cluster. This process has taken a few seconds. The funny thing is that application logs show we ...
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1answer
697 views

Galera Cluster - 3rd Quoroum Only Node - No Replication - Possible?HowTo?

I want to setup a 2 node cluster for MariaDB Galera cluster. What I read says it "requires" 3 nodes minimum. This is not correct, I am familiar with HA through using pacemaker, and basically, with ...
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1answer
873 views

Is it possible to have one Sql-Server cluster node in multiple Sql-Server clusters?

Is it possible to create FAILOVER CLUSTER A with Node01 (active) and Node02 (passive) and FAILOVER CLUSTER B with the same Node02 (passive) and Node03 (active)? I realized that SQL Server instances ...
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1answer
2k views

Failover and Failback SQL Server Log Shipping [closed]

I had a question on Log shipping Manual Fail over Let me explain about environment, Primary Server A (with Cluster setup A-P Mode) Secondary server B(DR server standalone). We had enabled Log ...
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2answers
1k views

High Availability Options For SQL Server

I'm looking to upgrade my single server SQL Server 2008 environment to a platform with much greater redundancy. The current system was put in 5 years ago when the company started and so was built down ...
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1answer
33 views

Mysql high safety implementation (replication or separate writes or something...)

I want to implement highly safe system storage with mysql. My case is: I need to store records. For more safety i want to have N separate physical mysql nodes. Then client save record and get OK ...
0
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1answer
13 views

Impact of table compression on HA Synchronous-commit mode scenarios

I am working with a HA SQL 2014 instance with Synchronous-commit mode. I did some table compression analysis with sp_estimate_data_compression_savings and I learned that table compression can be very ...
0
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1answer
121 views

Adding a geographically dispersed third node to an AAG cluster

We have a 2 node Always setup in our data center at DC and I have been tasked to setup a third node in this cluster in San Jose. What are the considerations I need to take to make this happen? I read ...
1
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1answer
624 views

AlwaysOn Availability Groups - Proper Quorum across WAN

I am evaluating the usage of AlwaysOn Availability groups with one node located in one data center, and another node located in a DR site. Both nodes are running in vmware on the same domain. I've ...
1
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1answer
285 views

Two active + one passive node for failover clustering

I'd like to know if it is possible to have a single passive node for two SQL Servers in a failover clustering deployment. For example, both active servers A and B will use server C as their contingent ...
3
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1answer
1k views

Shirking of Log file on Primary Server of Transaction Log shipping

I have a database with size 200 GB Total(mdf+ldf) and Log file(ldf) with 50 GB and 99% unallocated space in ldf file i.e. not being used at all. We had setup log backups for every 5 minutes, so there ...
4
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2answers
4k views

Does a replica set with only two machines make sense?

A lot of MongoDB tutorials, when they talk about replica sets, give examples of two machines: one originally initialized as primary, and another one originally created as secondary. As I understand ...
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3answers
71 views

Problem installing SQL Failover cluster

Let me first tell you my current environment in which there is one windows cluster on which there is sql cluster with two nodes, i.e, A and B in it. Of which, one A is active and B is passive. So, ...
0
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1answer
194 views

AlwaysOn Disaster Recovery Clarifications

Whenever I Perform a Forced Manual Failover of an Availability Group from PRODUCTION Servers(Sync) to DR/BCP (Asynchronous) node and test the connectivity and if everything is okay. I have two ...
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2answers
343 views

AG groups don't sync user DB collation change to replica servers?

We have 2012 AG group set up between server A and server B, where A is the primary, B is the replica 1) When we changed the user DB collation on server A, on server B, the user DB still shows the old ...
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1answer
2k views

ACCESS_METHODS_DATASET_PARENT Problem

We had an AlwaysOn Async replica we had some problems so we deleted the availability group After that the database and CPU seem to work abnormally It's very slow and we have waittype = LATCH_EX , ...
4
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2answers
3k views

SQL Server Always On or Mirroring & Log Shipping

We have two data centers with a 2 ms ping time between them connected by a site to site VPN. In the primary data center we have 2 servers, in the secondary data center we have a single database server....
0
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1answer
89 views

Postgresql: replica and HA

I've postgresql 9.4. I'm aware that there are many answer on DBA and SO, I'm aware of the wiki and the documentation. But anyway, I can't understand in a simple way what's the right way to have a ...
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1answer
2k views

High Availability SQL Server

We currently have a asp.net application running on a Win 2012 dedicated server, with a local copy of SQL 2014 Express. We are looking to add a second web server and have them in a NLB cluster. But ...
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1answer
3k views

SQL Server 2012 failover cluster node won't start cluster services

We have 2 node SQL server failover cluster setup in our environment. Node2 SQL server machine got shut down. I turned it back on and connect back to the failover cluster. It successfuly ...
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1answer
251 views

SQL Server mirroring / failover alternative [closed]

I am looking at building at reliable database with Microsoft SQL Server, with mirroring and automatic failover. The SQL Server here is standard version, not enterprise one so High Availability ...

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