Exchange Server 2003 - Backup and Recovery

By: Alan Maddison

Thanks to the growing use and importance of e-mail, IT managers have the unenviable task of keeping large volumes of files online or at least easily recoverable. E-mail storage is more than a convenience issue for users, as organizations need to comply with myriad legal and security considerations. Fortunately, for organizations that have moved to Exchange 2003, Microsoft has stepped up to the plate and added features and enhancements that help with the day-to-day problems IT managers face.

However, even with the latest technology, it is important to remember to document, document, and document all procedures, processes, and daily activities. Exchange administration can be difficult. Daily routines are often filled with problems that need fixing and users who need help. Urgent tasks overwhelm important tasks. Low-urgency chores such as documenting procedures, making sure users know what is expected of them, and planning for problems never make it to the front burner.

However, the increasing complexity of Exchange environments means we can no longer afford to put off important tasks. Our lives end up being a whole lot simpler if everyone knows what to do and what is expected of them.

This article covers the areas you need to document to help make your life simpler, as well as meet legal and security requirements. You'll also learn about the tools that will keep data safe, and if something goes wrong, you are in a position to recover the data.

Best Practices - Policies and Procedures

Successful Exchange management is more than getting through the day without annoying users. The best approach to e-mail administration is to look at the big picture and start managing e-mail systems actively. As mentioned previously, the big-picture approach requires documentation of policies and procedures, which many Exchange Administrators overlook.

The process of documentation formalizes and standardizes how IT departments are supposed to do their jobs. This, in turn, helps reduce downtime and errors. It also helps when problems occur, as formalization and standardization reduce the unknowns when troubleshooting. The process of developing and implementing policies that affect an Exchange environment's operation as well as how people use the system will involve many people beyond the messaging group. For example, defer security and legal requirements to the legal department and senior executives.

Your role in these matters is to advise on the technology required to meet legal and security requirements and monitor enforcement. For mundane matters such as e-mail storage limits, attachment sizes, and public folder creation, it is your responsibility to define limits based on your infrastructure. As always, prepare to deal with exceptions. Exceptions should always be well documented and understood as they often prove to be the source of problems.

Creating procedures is a very different process and is one for which the Exchange team is solely responsible. Procedures define the tasks we do and how we carry them out. Typically, Exchange related procedures can be grouped into four categories: Backup and restoration; Monitoring and analysis; System administration; and Change and configuration management. We cover backup and restore in a later section because of its importance. If all else fails and you have a well-documented and tested backup and restoration procedure, users will spare their wrath.

The purpose of monitoring and analysis is to measure and understand your hardware and software systems. Monitoring and analysis are central to maintaining a healthy system and preparing you for future changes. For example, without the hard numbers provided by monitoring and analysis, it becomes difficult to justify spending money on new hardware or hiring another administrator. A historical record helps you understand your hardware and software and what is normal behavior. This, of course, allows you to spot signs of trouble as they occur rather than waiting until users complain or systems crash.

Monitoring and analysis can be divided further into performance monitoring and availability management. Performance monitoring covers all of the fundamental measurements required to know how your system is performing and identify when there might be a problem. Examples of counters to measure in Performance monitor include CPU utilization, memory usage, pages per second, average disk queue length, and message queue length. This information allows you to identify bottlenecks and pinpoint trends. Availability management is about maximizing system up time and is tied closely to performance monitoring. Availability, reliability, and time-to-repair are the key measurements to track.

System Administration procedures are tasks completed regularly. Regardless of the tasks' frequency, the goal is to document the procedure so every administrator understands what needs to be done and how it should be done. Daily tasks include reviewing event logs, checking that backups completed, adding or deleting users, and reviewing alerts generated by performance monitor. Less frequent tasks include security reviews, testing backups, monitoring tape rotation, and database maintenance. Because many system administration tasks are repetitive one of your goals, should be to automate as many of them as possible. This will help reduce errors and increase your availability to handle unexpected problems. A key part of good system administration involves understanding the tools that you have at your disposal and how and when they should be used. Change management involves documenting and monitoring how and when changes are made to your Exchange environment. This includes research, review, and rollback plans. The goal of successful change management is to modify your Exchange environment without impacting users during or after the change. Changes are usually measured by their scope and potential impact. High Impact is defined typically as a company-wide impact and may require input from colleagues outside the messaging team. An example is a migration from Exchange 5.5 to Exchange 2003.

Medium impact changes affect one or more of the critical systems within the messaging environment. A great example of this is the patching and update process.

Low-impact changes are modifications in policies and settings that do not have any significant impact on your environment. Configuration management is tied to change management and is the process of maintaining records on software and hardware systems. Much of the information gathered as part of this process is critical if you are subject to an audit, such as financial, legal, or security.

Data Backup and Recovery

Fortunately, many vendors want to tackle the problems we face. Recent third-party software enhancements include software that allows for improved pattern recognition for searching e-mail and improved auditing capabilities to show that data has been accessed by authorized personnel only. Several Exchange backup vendors tackle the issue of granular recovery in a most effective method. These tools will allow you to mount backups and restore to live Exchange environments without interruption to service.

On the hardware side, some vendors advocate disk-based backup solutions. Tape has many disadvantages. The biggest, of course, is restoration speed. With the price of Networked Attached Storage (NAS) and Storage Attached Networks (SAN) coming down, these solutions become very attractive as a medium-term storage solution. When incorporated into your environment correctly, disk storage is cost effective and provides multiple layers of redundancy.

Some vendors provide block-level backup tied to policy implementations that prevent data from being deleted in contravention of company policies. When tied with the ability to create secure audit trails, these solutions provide a comprehensive solution to regulatory compliance. However, it is unlikely that tape will disappear because it still plays an important role for long-term storage. Moreover, unless you are backing up over a WAN, tape offers a good method of getting oodles of data off site. This, of course, is necessary for any adequate disaster recovery plan.

The downside to many spinning spindles is cost. Some organizations don't have the budget to replace hardware that seems to work properly by outward appearance. Unfortunately, most of us won't have the funding we want for the latest technology, so it is important not to overlook the fundamentals. Regardless of the tools you use, the procedures you follow and the standards you set that are more important than technology. In fact, the fundamentals of any well-run Exchange environment are universal.

Backup strategies

Before you slap a tape into a drive to backup an Exchange server, you need to understand the physical file structure of an Exchange storage group and how Exchange manages data in these files. Each storage group consists of two files: EDB and STM.

The STM file is a temporary storage point for SMTP mail that stores Multipurpose Internet Mail Extensions (MIME) content. Once an e-mail has been accessed by a MAPI client, such as Outlook, the content is stored in the EDB file.In addition to these two file types; Exchange uses log files as an intermediate step in the write-to-database process. These logs files help ensure data consistency, integrity, and performance. The log files are a critical component in the restoration process. In fact, it is only after a normal backup using an Exchange-aware backup client that these log files are deleted. One important item to note is that while Exchange supports circular logging; do not use this feature in a production environment because of the possibility of data being overwritten. Also remember that the System State needs to be backed up to facilitate the recovery process in the event of complete system failure. You will also have to backup the IIS metabase if your organization uses Outlook Web Access. While there are many Exchange-aware backup clients, (including NTBackup, which is a solid tool for smaller shops) the task of developing a backup strategy is the same regardless of the tool.

The three backup choices are full, incremental, and differential. A full backup is the best option to choose if you have the storage space and a sufficiently large enough backup window to complete the task. A restoration from a full backup is straightforward. It is also the fastest method of restoring your Exchange environment in the event of problems. An incremental backup archives the data that changed since the last incremental backup. This is the fastest backup method. You should use this method if you have a short backup window and are comfortable handling the additional complexity of a restoration. In the event of a system failure, you will need to have the last full backup and every incremental backup since. A differential backup represents a trade-off between a full and an incremental backup. As it will archive all data that has changed since the last full backup, it does not provide the fastest backup method. A restore will only require the last full backup and the last differential backup. While the process of backing up Exchange is straightforward, data recovery is not. The biggest challenge in recovery is recovering individual items or mailboxes. This is called brick-level backup and restoration. Unfortunately, this is one of Exchange's biggest drawbacks. The API approach developed by Microsoft provides only for backup up at the database level. While many products allow brick-level backups, be aware that performance will be dramatically slower when performing such a backup. Perhaps more importantly, brick-level backups should not be considered foolproof as they often have difficulty with open items, as well as third-party Exchange add-ins. Fortunately, Exchange 2003 makes the brick-level restoration easier than in earlier versions.

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