Disaster Recovery — Complete Guide

Disaster Recovery — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ADO.NET Core Tutorial on Toolliyo Academy.

8 min read Updated 8/21/2026

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ADO.NET Core Tutorial · Lesson 87 of 100

Disaster Recovery

Foundations ✓ → SQL & safety ✓ → Production ✓ → Projects

Projects · 4 — Portfolio builds · ~10 min · Module 9: Cloud and DevOps

What is this?

DR pairs failover (AG/geo) with ADO.NET connection string strategy and DNS/app settings cutover.

Why should you care?

ShopNest regional outage needs a practiced fail-over path.

See it live — copy this example

Use a .NET console or API project with SQL Server LocalDB. Run dotnet run after pasting.

// primary + failover partner in CS (AG) OR swap CS on cutover
"Server=tcp:shopnest-ag.database.windows.net;..."

What happened?

Document RTO.
Test failover.
Clear connection pools after cutover.
Read-only secondary rules.

Practice next

Document DR runbook.
Failover test quarterly.
Update CS / DNS.
Read-only mode flag.
Status page hook.

Remember

Failover plan. CS strategy. Clear pools.

ShopNest DR drill

Failover group cutover keeps API up.

Outcome: Measured RTO under target.

Interview prep for this lesson

Practice these questions aloud after reading—each links to a full structured answer.

Junior PDF Detailed

What is ADO.NET?

Short answer: ADO.NET (Active Data Objects .NET) is a data access technology in the .NET framework that enables applications to interact with databases and other data sources. Explain a bit more It provides a set of clas…

Mid PDF Detailed

Memory Efficiency:?

Short answer: A DataReader is a forward-only, read-only cursor, meaning it streams data from the database and does not store the entire result set in memory. DataSet, on the other hand, loads the entire result set into m…

Mid PDF Detailed

Optimistic Concurrency Control:?

Short answer: Optimistic Concurrency assumes that conflicts will be rare and allows multiple users to read and modify data without locking it. Explain a bit more When updating data, you compare the current data in the da…

Mid PDF Detailed

Using ExecuteReader (for a single row, multiple columns):?

Short answer: SqlCommand command = new SqlCommand("SELECT CustomerName, ContactName FROM Customers WHERE CustomerID = @CustomerID", connection); command.Parameters.AddWithValue("@CustomerID", 1); conn…

Mid PDF Detailed

SqlCommand: Used for SQL Server databases. It represents a Transact-SQL?

Short answer: command or stored procedure. Example: SqlCommand command = new SqlCommand("SELECT * FROM Customers", connection); Example code command or stored procedure. Example: SqlCommand command = new SqlCom…

All course Q&A Practice exams

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