Questions tagged [disaster-recovery]

A set of policies and/or procedures that enable the recovery or continuation of vital infrastructure and systems. Please be sure to include what DBMS you are using.

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which High Availability and Disaster Recovery method would be suitable for my SQL Express server

What are the considerations that would determine which High Availability and Disaster Recovery method would be suitable for my MSSQL express server? These are some of the considerations I found on the ...
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What is the general recommendation for sql server crash recovery from mdf/ldf vs backups for least data loss? [closed]

I'm learning steps to recover from sql server OS or OS disk crash. Assuming the OS or OS disk is corrupted and unrecoverable. I know that a HA solution like fci or ag is better suited to prevent such ...
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Database stuck in a read only state when testing a DR scenario with a multi-subnet SQL Server Always On AG, how can I get the db in a healthy state?

I am testing a disaster recovery scenario with azure VMs. I have sql servers deployed across 2 regions joined together via Always On availability groups sitting on top of a multi-subnet WSFC. When I ...
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Failing over to DR site Availability group

I have a 4 node cluster SQL 2012 availability group database with one witness server at the primary site. 3 nodes are in the primary site and one node in the DR site. Due to maintenance at the Primary ...
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Why would my MySQL replica server experience an sql integrity constraint error after losing connection and attempting to start again?

I have a master-master replication setup between two different servers using MariaDB. One is the primary server (server A) that is connected to my web applications, and the other is a replica that ...
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Sql server replication for HA and DR

1.)According to brent ozar's HA and DR chart,for Failover Cluster Instance - SQL Server minimum version supported and SQL Server minimum edition required is given as 'any'. Does that mean it works ...
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File Share Witness location

We have a 4 node availability group with 3 node on the primary data center and one node on the secondary data center. We want to add a file share witness and since we dont have a third data center and ...
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What is the correct configuration for the SQL Server listener with 2 nodes on-prem and 1 node in Azure?

I am setting up a 3-node Availability Group with 2 nodes on-premises and the 3rd on a VM in Azure. All nodes are SQL Server 2019 Enterprise with CU14. The Availability Group is fine and the listener ...
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Availability groups across sites: what happens if severs can't contact each other but both still can reach file share witness?

I'm currently planning a new SQL Server 2019 Enterprise Edition setup with HA/DR, possibly with availability groups. Let say we have the following setup: Site A: one SQL Server instance (SQL1) Site B:...
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AlwaysOn availability group listener

There is a server with me that is already configured with AlwaysOn by somebody else. I am adding one more availability group to the server. Can I use the same availability group listener for the new ...
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What is the reason to backup master, msdb and model system databases? [duplicate]

What is the reason to backup master, msdb and model system databases? How does it help during disaster recovery? And are they to be restored just like user databases?
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What is the equivalent of on prem ha dr solutions in the azure cloud PaaS and SaaS?

On prem ha dr solutions are: Log shipping Mirroring Replication FCI AG What is the equivalent of each of the above in the azure cloud PaaS (azure sql managed instance) and SaaS (azure sql ...
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Is there any sql ha dr solution that allows write to multiple servers?

I am looking for a sql ha dr solution that allows users to write to multiple replicas. Is this possible in sql server? For example: AG allows read from multiple replicas. But write only to primary ...
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Do I need to be carefull about log shipping log backups truncating tlog?

We have full backups running every Sunday. Differential every day. Log backups every hour. This is all configured as part of our recovery strategy. I have been requested to configure log shipping on ...
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What is the advantage of full backup over snapshot backup when it comes to restore by applying tlog?

What is the difference between following restore options: A. Full backup and applying to it subsequent log backups. B. Snapshot backup and applying to it subsequent log backups. Note: this is not ...
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Connect two Percona XtraDB Clusters in two data centers

I have been trying to figure this out the past couple of weeks. We used to have a five-host Percona cluster at different providers. When it started acting up I read that it is a bad idea to have ...
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Deleted Postgresql Data Directory

PostgreSQL data directory was accidentally deleted. Right know I'm using photorec to recover all the files in the disk. I also know from the docs the structure of that directory. There are text files ...
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Why is FCI not considered to be a DR solution? [duplicate]

FCI is said to be an HA solution. If one node crashes, it spins up the 2nd node so why is it said to not be a DR solution? There was a disaster at node 1 and node 2 picked up from there. Isn't that ...
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HA options for a VLDB

We have 2 VLDB's - 6TB (primary db, not much OLTP traffic) and 4TB (archive db). Data will be moved/archived (delete from primary and insert to archive) daily from 5 large tables. Currently this ...
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How do I recover data from the postgres data directory on my hard drive?

I had an old iMac which stopped working a while ago I take weekly backups of the database I was updating which contains feed items from several rss feeds I am still missing the data for the last week ...
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Log files in Always on Disaster Recovery Situation

In my Always on Avaliability group setup there are four nodes in the cluster in two datacenters, an avaliability group has for replicas, one on each node. Two replicas in the same datacenter have sync ...
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How to ensure backups are successfully persisted to S3 when using Ola Hallengren solution on AWS EC2 Instances

Improving Existing Backup Approach By Using Ola Hallengren Backup Solution Deploying a new backup approach to eliminate dependency on a vendor tool (Cloudberry) that I've leveraged before. In my ...
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Mysql trying to drop table and how to recover data?

I have on lamp setup where suddenly I see all the database files are missing and gone and when I checked the error logs I can see few of this lines. InnoDB: Error: table `com`.`#sql` does not exist in ...
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Corruption of files in postgres: The database subdirectory "base/13067" is missing

Right, my PostgreSQL database 11.1 is on top of a GlusterFS. My GlusterFS break, my backup was being done on another table and I don't have backups anymore. I started the database on a docker ...
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SQL alwayson AG Disaster Recovery

Need advise on below: I have 2 node alwayson AG on Primary Sync mode in the current configuration and fsw is in Primary DC only Actually during Switchover the entire DC 2 node and fsw will be down ...
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PostgreSQL WAL Archival Best Practices?

The postgresql documentation gives an example archive_command of archive_command = 'test ! -f /mnt/server/archivedir/%f && cp %p /mnt/server/archivedir/%f' # Unix but adds the disclaimer ...
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AlwaysOn availability group DR failover with Powershell

I am setting up AlwaysOn availability group for Disaster Recovery (DR) in the test environment. For AG1, node1 and node2 (synchronous commit/automatic failover) are in DC1; node 3 and node 4 (...
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Good practices for patching SQL nodes in High Availability solution [duplicate]

Our database structure utilizes two roles in the Window Failover Cluster Manager. One is for FCI - switching between the active/passive node in the Primary Data center. One is for SQL Availability ...
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SQL server Log Shipping

I have two node SQL server standard failover cluster. I need to setup single node DR using log Shipping method. Want to ask after switch over to DR how we can setup, plan so that application can ...
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SQL server alwayson 3 Node Primary Down

I am using three node alwayson Availability Group SQL 2012 Enterprise Edition. 2 Node in DC with File Share Witness quorum also in DC and third node to be setup in DR I need to perform a DR switchover ...
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Splitting file groups of large SQL Server database using FileStream

Background: I have a SQL Server database which is storing documents in the file stream. These documents are usually accessed via Web API by Mobile Apps and Modern JS Apps. The size of the database ...
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SSD used for tablespace died. How can I recover data?

I have a postgres cluster with two databases Database A uses the default tablespace. It holds important information but has very few writes per day (< 20) and only has a few tables with a few ...
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Why distributed AG is preferred to normal AG for cross datacenter failover scenario?

I have two node WSFC and currently I'm working on DR solution with availability group.I already read microsoft doc about distributed AG.So my question is what are benefits of using distributed AG ...
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Why do I need witness in WSFC with two nodes?

I have Windows Server 2019 and SQL Server 2019 running in both nodes of my cluster. In my case everything is working fine without witness. I need Windows Server Failover Clustering (WSFC) for ...
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Database Mirroring - Will forcing the service only lose non-committed data?

I have a database mirroring session in high safety mode between Server1 (Primary) and Server2 (Secondary) According to this, synchronous data mirroring means every transaction committed on the ...
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How to maintain a query that runs forever?

I would like to run a query that finds prime numbers, and I would like to run it forever. @Solomon Rutzky on this page Prime numbers in a given range , give us a good example of the Sieve of ...
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MySQL database backup plan

I have a MySQL database that is about 17GB in size. Right now we don't have a backup for this and I have been tasked to look into backing it up automatically. I am a software developer myself, not an ...
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Disaster Recovery through cloning drives in sql server 2014 enterprise

I am a DBA noob and recently my work has considered to have a disaster recovery plan for their production DB lets say A (sql server 2014 enterprise). The production server A and Disaster recovery ...
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1 vote
1 answer
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Is it safe to restart PostgreSQL if process terminated for some reason?

I am writing a docker-compose config with a container with PostgreSQL in it. docker-compose has a configuration options called restart. If I enable it then whenever the Postgres process stops it will ...
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Log Shipping between 2 AGs

I'm having one AG with two nodes (active-passive) in one data center and another AG with two nodes (active-passive) in a different data center. I need to have log shipping enabled between these two ...
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7 votes
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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 ...
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Transaction Replication as DR solution

I have a production database server and a failover database server set up. All the transactions from the primary production db server is being replicated(transactional replication with initialize ...
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How to setup a SQL Cluster between 2 sites in active passive mode without shared storage

we need to install SQL at 2 sites, 1 primary and 1 DR. We don't to pay for license for the DR and need to know how will we setup a SQL cluster/replication/alwayson/bag or any other method that will ...
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-1 votes
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Accidentally overwrote mysql database with empty data [closed]

I accidently imported an empty database backup file into the same database, using mysql-workbench. Is there any way to undo this and get the data back? The backup available is 4 months old which is ...
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What are the potential issues after data or log disk failure?

Scenario: A client recently had an issue with an Azure VM where the (non-OS) 'premium' storage disks were erroneous removed without warning by Microsoft. This is the virtual equivalent to the hard ...
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1 vote
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Always On Availability Group Failover Issue

I'm testing a PowerShell Disaster Recovery script and trying to fail over to an off-site AG DR (asynch) replica with this command ALTER AVAILABILITY GROUP [MyAG] FORCE_FAILOVER_ALLOW_DATA_LOSS On ...
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6 votes
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Restore mongoDB by --repair and WiredTiger

We accidentally deleted the directory rm -rf /data/db which was our MongoDB path, and thanks to extundelete, we recovered it and got the directory /data/db. Here are our files in the directory, and ...
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Recover a mongo database deleted by rm

My developer accidentally lost our database by a bash script, which turned out to run rm -rf /* (see this thread). Thanks to extundelete, he just recovered the /data/db/ folder: However, he could not ...
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I am trying to achieve a Disaster recovery for Mongo DB

Right now i have a MongoDb HA in site one and i need another site with asynchronous replication enables in another location.This is a base plan of mine to achieve a disaster recovery . I dont have ...
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4 votes
1 answer
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Attach ldf more current than mdf

Is it possible to create a database where the ldf is more current then the mdf? Or to attach the older (more mature) ldf to the younger mdf (less mature)? I am working on Steve Stedman's Week 3 ...
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