EXECUTIVE SUMMARY
Microsoft SQL Server has become the data management tool of choice for a wide range of business critical systems, from electronic commerce to online banking to just-in-time manufacturing to streaming media.
There are many expensive, complex approaches and technologies that promise availability for SQL. Fortunately there are also simple, automated ways to get the highest levels of protection. The following five secrets to affordable SQL availability will help you to implement a SQL environment with little or no downtime, zero data loss, and no added IT complexity.
#1: Preventing downtime is better than recovering from
failure
You want to keep your SQL applications running continuously and avoid losing any data. However, most availability technologies work like airbags in a car. They are designed to mitigate data loss and minimize recovery time after the fact. The failure still happens. SQL downtime still occurs and some data—particularly data that is in-transit at the time of failure—is lost. Examples of these types of “fail first, then recover” technologies include tape backup and restore, replication, hot stand-by, and even clusters.
A better solution focuses on prevention of failures. Consider more modern availability technologies that enable the SQL application to operate continuously through a failure event so there is nothing to recover from and no data loss. This technology can even allow you to repair and restore failed server components or network connections while continuously online.
Five Secrets
#2: You don’t have to choose between downtime and data
loss
Optimally, you want to protect your SQL application and any application(s) running on it, your operating system, and all of your data.
Most technologies are designed to protect either your applications or your data. Few protect your OS and fewer still protect all three. For example, data backup provides some data protection, but requires a full application restart and data recovery, meaning a long Recovery Time Objective (RTO). Clusters move operations from a failed server to a stand-by server, possibly lessening, but not eliminating the
interruption in application service. Applications in a cluster are still vulnerable to faulty I/O from device drivers and a wide range of other threats.
Choose a software solution that keeps your OS running when a server fails, maintains application availability even when devices fail—without loss of application “state”— and ensures that all of your application data is protected.
#3: “Testing, testing, one, two, three…”
Gartner analysts stress the importance of routine testing of your IT infrastructure in preparation for a failure or disaster. Unfortunately, with many technologies, that means a full restart—aka downtime—for your SQL applications. Without this testing you have no way of anticipating scenarios that will render these technologies useless.
In a common scenario, a Windows administrator updates or changes something on one cluster server without meticulously performing the same task on the other server. As a result, the cluster failover process does not engage at all in the event of a failover.
#4: Don’t discount the human factors
Focus on two human factors: those that cause downtime and those that restore uptime and a protected environment. According to IDC, human error accounts for as much as 25% of IT downtime.
Systems that provide automatic uptime protection eliminate your reliance on a small number of key employees to restore operation. Although some technologies have automatic failover capabilities, they require IT staff to perform extensive disaster scenario testing to keep them operational. Disaster tolerant technologies continue to operate though disasters, eliminating the need for human intervention and allowing repair and replacement of damaged components while continuously online.
Restoring service is not just recovering data and restoring availability of the application. For traditional technologies, this may involve bringing systems back to their fully protected state. You may need to replace damaged server hardware, restore lost data, replace redundant network connections, and/or reload applications or an operating system.
#5: Use automated SQL availability
Choose an automated solution that continuously monitors and protects the entire SQL Server application environment, from storage and servers to applications and data. By completely automating the availability solution, you can protect yourself from human errors (secret 4), while preventing both downtime and data loss.
An automated solution should meet the following requirements:
1. It should continuously monitor the entire application environment. 2. It must respond appropriately to faults as soon as they arise.
For the most critical SQL applications, it should be able to survive the failure of an entire system without any data loss or service interruption. It should not require any application changes (introducing the possibility of human error), or any updates as you change or modify applications. A truly automated solution will not only improve availability, it should also deliver a low total cost of ownership, as it removes the need for specialized skills and staff time for maintaining availability and reacting to
everRun 2G: Automated Availability for SQL Server
Marathon’s everRun® software provides a completely automated path to SQL availability. Hundreds of organizations have deployed everRun to protect their SQL applications from hardware failures, software failures, and disasters. They’ve found everRun to be less expensive, simpler to operate and maintain, and more effective than any other availability solution they’ve evaluated.
everRun 2G is a single, comprehensive availability solution that protects storage, networks, systems and data in both single and multiple workloads. It works with a wide range of Windows Server environments, using off-the-shelf hardware and software. It synchronizes two standard Windows servers—including the OS, the SQL application, network interfaces, storage, and data—into a single operating
environment with full hardware redundancy.
everRun software prevents interruptions and downtime by fully automating fault management, so that your SQL applications never see the failures. This design enables support for any SQL application without the need for customization or scripting. You simply install your SQL application and you’re done.
everRun is a great choice for protecting Microsoft SQL Server and related database applications, offering:
• Higher levels of SQL Server availability than competing failover solutions • A single solution for both virtual and physical environments
• Selectable fault-tolerance with the ability to choose the level appropriate for each application
• Simple installation and automated management with no need for specialized staff experience or training
• Choice of either locally-attached or networked storage
• Built-in failover policy and sophisticated error detection that is faster and more reliable than simple failover heartbeats
And if you need to implement fault tolerance in the case of major, site-wide outages, use everRun 2G’s SplitSite® option to enable continuous availability between geographically dispersed locations. With SplitSite you can ensure that you still meet compliance and production requirements even if your primary data center is hit with a metropolitan-wide disaster. Geographic fault tolerance enables continuous operations even when a whole site is down.
To sum up, everRun is ideal for SQL availability:
Automated SQL application availability – Easy to operate and maintain. All fault
handling and policy management are automated for you.
Superior availability – We’re up. Always up. No loss of SQL application state. No
loss of data.
Affordability – Getting started is up to 36% less than other options. Administration
and maintenance costs are up to 55% lower than they are with clusters.
Non-intrusive – Works with standard x86 servers, no application or OS modifications
required. Supports any SQL app – no cluster awareness or scripting required.
Remote availability – Install our SplitSite option to geographically disperse your SQL
servers.
To see everRun in action, watch our product demo videos, or download a free 30-day evaluation
