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Many companies don’t really consider the bloating of server operating systems as a real problem to be addressed. This is wrong because as soon as you write any data to disk, you’ve just signed up your company to safeguard that data multiple times (3-90) for the next 3-5 years, if not longer.

How did I come up with this?

Assumptions – hopefully realistic for your situation

• Windows 2008 Server – 20GB installation for the OS only (MS says 32GB of disk is the min)
• Data is stored on a SAN, so we will ignore it. The size of data isn’t the issue in this article.
• Compressed and incremental backups are performed with 30 days retained.
• At least 1 copy is maintained off site for DR

Break down of backup disk use

• Install image – 20GB of storage
• OS Backup – 20GB of storage
• Off site Backup – 20GB of storage
• 2 extra copies of backup – 40GB of storage

Total is 100GB of storage media for a single Windows 2008 Server install. Not all that bad, really. Then consider that even small businesses probably have 5 computer servers, that becomes 500GB of storage. Still not so bad. Heck, your DR plan is just to copy the last backup to an external drive and take it home every Friday. Good enough.

Now imagine you have 50 or 100 or 1000 or 20,000 installations. Now it gets tougher to deal with. Those simple backups become 25TB, 50TB, 500TB and 10PB of storage and you haven’t got anything but the OS backed up – no data.

Alternatives?

1. Data deduplication on archive storage frames
2. Fixed OS images – if they are all the same, you only need 1 backup
3. Use a smaller OS image

Data Deduplication

Data Deduplication has been an expensive option that small companies with normal data requirements wouldn’t deploy due to cost, complexity and lacking skills. This is about to change with the newest Sun ZFS that should be out early 2010. It is already available in OpenSolaris, if you want to get started with trials. I’ve seen demonstrations with 90% OS deduplication. That means for every added server OS install, you only add 10% more to be backed up. Obviously, this will increase whenever a new OS or patch deployment over weeks and months occur, but this solution is compelling and will easily pay for itself with any non-trivial server infrastructure.

Fixed OS Images

This is always a good idea, but with the way that MS-Windows performs installations, files are written all over the place and registry entries are best applied only by installation tools. Configuration methods on Windows tends to be point and click, which can’t be scripted effectively.

On UNIX-like operating systems, base images can be installed, application installation scripted and overall configuration settings scripted too. There are a number of tools that make this easy, like Puppet. This is FOSS.

Use a Smaller OS

Xen Ubuntu Linux 8.04.x running a complete enterprise messaging system with over a years worth of data is under 8GB including 30 days of incremental backups. Other single purpose server disk requirements are smaller, much smaller. This blog server is 2.6GB with 30days of incremental backups. That’s almost a 10x factor smaller than MS-Windows server. Virtualization helps too. JeOS is a smaller Ubuntu OS install meant for virtual servers.

No Single Answer

There is no single answer to this problem. I doubt any company can run completely on Linux systems only. Data deduplication is becoming more and more possible for backups, but it isn’t ready for transactional, live systems. Using fixed OS images is a best practice, but many software systems demand specialized installation and settings which make this solution exponentially complex.

A hybrid solution will likely be the best for the next few years, but as customers, we need to voice our concerns over this issue with every operating system provider.