When most people think of a backup strategy they think about tape rotation and backup schedules. While these are important parts of a backup strategy they're not the whole story. As an organization begins to assimilate more and more servers, a reliable backup strategy becomes more challenging. Instead of one tape drive that backs up the entire network, libraries become necessary. Instead of doing one backup job and schedule, you need several. Here are four fundamentals for developing your backup strategy.
Plan for growth
Most organizations have begun to start monitoring their disk storage needs. While disk storage is cheap, the cost of maintaining all those files, including archives and backups, starts to become a real expense. When an organization plans its disk needs, it needs to review its growth and determine how much extra disk space will need to be purchased over the next year.
But here's the rub. Adding more disk space is relatively easy. You just add new drives to the disk array or you swap out smaller disks for larger ones. The process takes time but it's relatively transparent. Upgrading tape capacity isn't so easy for most organizations.
The hard part to stomach is that the cost of your tape drive system may exceed the direct costs of your disk expenditures. Because of expensive libraries, drives, and cartridges, backing up a system can often cost more than the disk drives for an organization. Because of this, it's difficult to make the up-front investment necessary for scalable growth — but it's a decision that will have a substantial impact on the amount of backup protection that is purchased next year. When developing your backup strategy don't forget to develop a strategy for containing your overall disk storage requirements.
Keep it simple stupid
The cornerstone of a backup strategy is the men and women who change the tapes in the drives on a routine basis. Whether you have a library that holds dozens of tapes or a single high-capacity backup drive, the tapes must eventually get changed. Because changing the tapes relies on humans it is, frankly, one of the more common areas for a backup strategy to fail. Your tape rotation strategy should be simple so that the potential for mistakes be minimized. The more complex the strategy, the greater the opportunity that it will be messed up.
Although backup programs today support all kinds of media retention policies, the reality is that most people really only understand simple rotations. Doing daily tapes, weekly tapes, and monthly tapes are often effective. This backup mechanism is the venerable grandfather-father-son rotation that most in the industry have used. The beauty of this rotation scheme is that sets of tapes can be labeled for insertion on a specific day which is marked on a calendar. The tapes that are inserted on that day are marked and all of the other tapes are removed.
If something does go wrong with the rotation it's easy to review the calendar and the tapes and determine what happened and how to get back on track. Trying to sort out a more complex tape rotation scheme can be difficult — even with the help of software.
Another critical factor to a backup strategy is the systems — both automated and process based — that you have in place to know when the backup is failing. On the surface, this problem appears simple — have the backup software send you a notice when there is a failure. Certainly this is better than nothing, but what happens if none components of the backup software are running — including the one responsible for sending e-mail? You won't get any e-mail telling you there is a problem because the portion that does that isn't working either. I've seen this happen to more than a few clients.
You need to have systems that generate messages on success as well as failures. While you may not need to read through each line of a backup log if the software indicates the backup was successful, you do want some kind of positive confirmation that the backup did indeed complete. Fifteen years ago, this meant printing the backup log and putting it into a book each day. It became routine for the operations staff to put this into their book — when it was missing it was noticed. Today, we have e-mail notifications which means there isn't a log book, but if directed at a specific person (or group) the notifications can become just as effective. If they have to move the logs to a folder each day it is a repetitive process that gets noticed when it doesn't happen.
On that note, it's good to have someone responsible for verifying that the backups run and a backup person who's responsible when that person is gone.
Of course, even better than notification on success as well as failure is a checklist of daily tasks which includes verifying the backups ran. However, in most mid-sized IT shops these daily task lists never seem to get created or used.
Managing multiple backups
In today's environment, having a single backup solution is often wishful thinking. Products like Windows SharePoint Services and the limitations of the backup agents, often mean that you're backing up with multiple different programs, sometimes from the individual backup programs to disk and then from disk to tape.
One of the most frequently overlooked issues is verifying that these ancillary backups are running correctly. They should be subject to the same monitoring requirements that the rest of the backup strategy is. However, often because these are cobbled together from scripts and built in tools they often lack any form of notification. This is one of the greatest potentials for problems since it's often difficult to spot when the backup hasn't run successfully. Remembering to address notification in each one of your backups is a key component to a solid backup strategy.
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