Windows Server 2012 : Backup and Recovery (part 2) - Developing backup strategies

So, where to start? Start by outlining a backup and recovery plan that describes the servers and the data that need to be backed up. Ask yourself the following questions:

The answers to these questions will help you develop your backup and recovery plan. Often you’ll find that your current resources aren’t enough and that you need to obtain additional backup equipment. It might be one of the ultimate ironies in administration, but you often need more justification for backup equipment than for any other type of equipment. Fight to get the backup resources you need, and do so without reservation. If you have to make incremental purchases over a period of several months to get the backup equipment and supplies, do so without hesitation.

In most cases, your backup strategy should involve performing some type of backup of every server daily and full backups of these servers at least once a week. You should also regularly inspect the backup log files and periodically perform test restores of the data to ensure that data is being properly written to the backup media.

Plan separate backup strategies for system files and data files.

Administrators often back up an entire machine and dump all the data into a single backup. There are several problems with this strategy. First, on non–domain controllers, system files don’t change that often, but data files change frequently. Second, you typically need to recover data files more frequently than system files. You recover data files when documents are corrupted, lost, or accidentally deleted and can’t be recovered using other means, such as Previous Versions. You recover system files when you have serious problems with a system and typically are trying to restore the whole machine. Sometimes, however, rather than restore a failed server, it might be faster and easier to set up a new server that provides the same services. For example, with a domain controller that doesn’t perform any operations master roles, you might be able to set up a new domain controller from media faster than you can restore the original failed domain controller.

Look at the timing of backups as well. With earlier releases of Windows, you are often concerned about the time that backups are performed. You want backups to be performed when the system’s usage is low, so that more resources are available and few files are locked and in use. With the advances in backup technology made possible by the Shadow Copy API built into Windows Server, the backup time is less of a concern than it was previously. Any backup programs that implement the Shadow Copy API allow you to back up files that are open or locked. This means that you can perform backups when applications are using files and no longer have to worry about backups failing because files are being used.

When it comes to backup, there is no such thing as a one-size-fits-all solution. Often you’ll implement one backup strategy for one system and a different backup strategy for a different system. It all comes down to the importance of the data, the frequency of changes to it, and how much data there is to back up on each server. But don’t overlook the importance of recovery speed. Different backup strategies take longer to recover than others, and there might be differing levels of urgency involved in getting a system or service back online. Because of this, I recommend a multipronged backup strategy that is optimized on a per-server basis.

Key services running on a system have backup functions that are unique. Implement and use those backup mechanisms as your first line of defense against failure. Remember that a backup of the system state includes a full backup of a server’s registry, and that system configuration includes the configuration of all services running on a system. However, if a specific service fails, it is much easier and faster to recover that specific service than to try to recover the whole server. You’ll have fewer problems, and it is less likely that something will go wrong.

Specific backup and recovery techniques for key services are as follows:

The availability, scalability, are your next line of defense. Take the time to develop plans and procedures that can help you through everything from a power outage to the worst-case scenario. Don’t forget that when you use BitLocker without Network Unlock, protected computers are locked until you provide the necessary recovery password. When a computer is locked, you must use the recovery password from a USB flash drive, or use the function keys to enter the recovery password. F1 through F9 represent the digits 1 through 9, and F10 represents 0.

Finally, you also need to perform regular backups of both system and user data. Most backup programs, including Windows Backup, which is included in Windows Server 2012, support several types of backup jobs. The type of backup job determines how much data is backed up and what the backup program does when it performs a backup.

The basic types of backups include the following:

As part of your backup strategy, you’ll probably want to perform normal backups on a weekly basis and supplement this with daily, differential, or incremental backups. The advantage of normal backups is that they are a complete record of the files you select. The disadvantage of normal backups is that they take longer to make and use more storage space than other types of backups. Incremental and differential backups, on the other hand, use less space and are faster because they are partial backups. The disadvantage is that the recovery of systems and files using incremental and differential backups is slower than when you only have to perform a recovery from a normal backup. To see why, consider the following backup and recovery examples:

As part of your backup strategy, you might also want to use copy backups to create extended backup sets for monthly and quarterly use. You might also want to use a media rotation scheme to ensure that you always have a current copy of your data as well as several previous data sets. Although tapes traditionally have been used for backups, more and more organizations have been using disk backup instead of tape backup as disk drives have become more affordable. With disks, you can use a rotation schedule similar to the one you use with tapes.

The point of a media rotation scheme is to reuse media in a consistent and organized manner. If you use a media rotation scheme, monthly and quarterly media sets can simply be media sets that you are rotating to off-site storage. Consider the following media rotation scenarios: