As a web developer or website owner, you might have faced server outages or may have been told that there will be an outage period for a number of days by your hosting provider. But what if this server fails all of a sudden due to some reason and what if you need your website to be up and running especially during festive season?
When you are expecting a lot of traffic and sales from your website, you will need to be a bit smarter in understanding the nuances of your server and be prepared in case there is a failover. With this article, we will understand what a server failover is, what are its types and how to overcome it with trouble shooting.
What is server failover?
Server failover means that the server is automatically ready to take over when the primary server is offline. The failover server acts as a backup generator. In the event of a power outage in your home or building, a backup generator temporarily restores power. Likewise, in the event of a server failure, if the primary server goes down, the secondary server takes over.
The purpose of a server outage is to increase the availability of a network or site or to increase its ability to continue operating in the event of a failure of one of its components.
The main function of a server is to store content and data and share it with other computers.
What are the different types of servers?
Webservers, Proxy server, Virtual Machines (VMs), FTP servers (File Transfer Protocol), Application Servers, File Servers, Database servers, Mail servers are some of the types of servers used in the web hosting world. Within web servers, shared, VPS servers, dedicated servers, cloud servers being the most prominent.
Even though there are many different types of servers, web servers are the most popular because they keep websites and applications running. If the web server crashes, it cannot process the request and therefore cannot send data to the client. There are no server errors and server errors can cause download errors or website crashes.
Why do servers fail?
Servers can fail for many reasons: power outages, natural disasters, cyber-attacks (e.g., distributed denial of service (DDoS)), and hardware problems (e.g. cabling or overheating) that IT staff encounter. It can be very predictable. If a server goes down, nothing works.
In this case, delivery errors are inevitable.
Failover is a backup feature that helps prevent complete failures. Failure often involves a process called load loss. Load adapters improve application availability and performance by distributing traffic across two or more servers. Many load managers do their best to monitor the status of their servers and assign requests to the servers that handle the traffic.
When a server fails, you need to connect it so that it can detect the problem and make the necessary changes. You can connect a physical “heart” cable to the server to enable analysis, such as a heart rate monitor that monitors a person’s heart rate.
The server can be controlled via the Internet. For example, Cloudflare periodically sends HTTP/HTTPS requests to a group of servers to check the status of the load-balancing servers. If an HTTP/HTTPS check indicates the server is down or offline, Cloudflare will redirect traffic to an available server.
Depending on your configuration, the fault behavior will differ slightly. The server failover configuration is active, active, or on standby. A backup server is an active server consisting of a primary server and one or more servers. In a two-server configuration, the second server controls the first, but less. When the secondary server detects the changes on the primary server, it takes over and notifies the data center that the primary server needs to be reset. When the primary server recovers, it regains control and the secondary server remains in standby mode.
The continuous operation of the master server is called a failover. Running to configure two servers, both servers must remain active. Combine functional design and load design when configuring load balancing servers. If the server fails in a busy configuration, traffic is redirected to the production server.
What issues do we face usually and how to troubleshoot them?
Issue: If SQL Server is installed on a different port, you will not be able to connect to the network.
Problem 1: The SQL Server user account cannot log in to the admin domain.
Solution: Check the event log for signs of network problems, such as adapter errors or DNS issues. Make sure you can ping the control panel.
Problem2: The SQL Server service account password is not the same on all cluster nodes, or the SQL service node migrated from the failed node does not restart.
Solution: Use SQL Configuration Manager to change the SQL Server user account password. Otherwise, if you change your SQL Server account password on one node, you must also change the password on the other node. SQL Server Configuration Manager does this automatically.
Issue: SQL Server cannot access the cluster disk.
Issue 1: Firmware or drivers are not up to date on all nodes.
Solution: Make sure all nodes are using the same driver version as the correct OS version.
Issue 2: A node cannot recover a cluster disk that has been moved from a failed node to a cluster disk with a different drive letter.
Solution: The cluster disk drive letter must be the same on both servers. If not, check the initial installation of the operating system using Microsoft Cluster Services (MSCS).
Issue: Error caused by SQL Server service failure
Solution: To prevent a single service failover from causing a SQL Server cluster, use Windows Cluster Manager to configure the service as follows: Under Advanced, select the check box Exclude impact on the group. Choose. Full-Text Properties dialog box. However, if there is a problem with SQL Server, the whole search will continue.
Conclusion
Here is hoping that you have understood what a server failover is and what are its meaning types and troubleshooting ideas if you come across problems. In case of any queries, please share them in the comments section below.
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