Monday, August 23, 2010

Backups: What and How

For this second week's topic, I thought that we should discuss backups. Every IT administrator I have ever met has had the fundamental need to have a backup of everything firmly engrained in their psyche. Some have had this need handed down from those before them; others from direct experience of not having them. Regardless of your past experiences, this need is likely there; but does everything in the environment need to be treated the same way? Most backup programs seem to think so; otherwise, there would be simpler and cheaper ways within their systems to have multiple media rotations and better support for "cheap" USB media for some materials.
Tape has a very proven track record and I am not saying that tapes should be avoided by any means. I am merely suggesting that tape may not be the best media for some of the data in an organization. Tape is an excellent method of retaining data for long periods of time, but is that really needed in all cases? Individual tapes have a relatively short life span when you look at the number of "write cycles" they support. As a result, tape becomes rather costly when it comes to backups with a short retention time as you just end up replacing the tapes in that rotation much more frequently.
If you take a hard look at the data in your organization that should be backed up, you will likely find that you can divide the materials into 2 categories: Data with a long-term retention need and data with only an immediate disaster recovery need.
Most user data (home drives, file system shares, mail, etc.) is going to fall in the first category. This is because one could reasonably expect a legitimate request for what a particular folder or mailbox looked like 3 months ago. It is this type of data that most backup systems are really meant to handle.
A fair number of items that fall within the IT group though do not have a need for that type of long-term retention. Would you really ever have a need for what drivers a print server was using 6 months ago? Would you really have a need to restore a workstation with an image that was replaced a year ago? These items really only need to be backed up to handle equipment replacements in the event of a disaster, so you only need to keep as many copies as is necessary to ensure that your DR need is met. Items that will likely fall into the DR-only need for your organization:
  • Print Server Configs
  • AD Backups
  • Infrastructure (Switch/Router/Firewall/etc) configs
  • System Images
  • Software Installation Packages
  • Archive Materials
There may be others in your environment not even mentioned here. As several of the items mentioned can be quite large, they may be unnecessarily adding significant time and volume to your normal backups that could force you to upgrade either backup products or tape media/drives before it is really necessary. These materials can easily be handled in other ways. Here are some alternative suggestions to traditional tape backups:
  • Incremental copies using a utility like ROBOCOPY or RichCopy to a USB Flash Drive/External Hard Drive that can be stored offsite
  • Cloud-based backups from companies like Carbonite, iDrive, or Axcient
  • Simple, offsite DVD copies of materials that don't change frequently, like system images
  • A monthly tape rotation that is only kept for 2-3 months
And there are likely more. For some of the items, like the Archive Materials, the most cost effective means of backup within your organization may simply be a monthly tape backup due to their size. The point is simply that you don't need to burden your normal tape backup with the materials that don't have a long-term storage need. Just make sure that whatever mechanism that you select doesn't burden you.

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