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
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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