For many years now I have been almost an advocate for Redhat Enterprise Linux (RHEL) in the corporate environment and Ubuntu or some other random Ubuntu variant for home users. I’m not saying one is better than the other, and given my desire for simplicity and easy of migrating between work and home, why not recommended Fedora for home users. To be honest, its too bleeding edge for your average user to gain traction with. The average user can not and will not deal with having to install an OS only to find out there is over a Gb of extra updates that need to be applied before they begin doing anything else.

Recently I have had the need to investigate alternatives to RHEL, but where to start, where to go. Just look at the branches available for distributions.

For most people in a corporate environment moving from Redhat to a completely different base is out of the question. The changes involved with moving from Redhat to say Debian or Slackware is an exceptionally daunting task. For those that use Linux is a basic sense, and by this I don’t mean looking good on your desktop, but using it for web servers or database servers the move might be rather simple and straight forward. As a sysadmin migrating between Redhat, Ubuntu and Slackware isn’t an issue. Yes admittedly I do often type apt-get install on a Redhat box, or yum whatprovides on a Ubuntu box, but at the end of the day the similarities in “use” are rather easy to switch between when needed.

So if not Redhat then what? Following RHEL and Redhat Linux as the base you are left with very few choices. aLinux, Asianux, CentOS, ClearOS, Fedora, Fermi Linux LTS, Mandriva Linux, Miracle Linux, Oracle Linux, Red Flag Linux, Rocks Cluster Distribution, Scientific Linux, SME Server & Trixbox. We can easily discount aLinux, Asianux, Red Flag Linux & Trixbox. I’m not saying there is anything wrong with these distributions in their home markets and applied for their original designed purposes I’m sure they are 100% fit for purposes. However a corporation attempting to migrate from Redhat to any of these may not be a wise choice.

This leaves us with CentOS, ClearOS, Fermi Linux LTS, Mandrake Linux, Oracle Linux, Scientific Linux & SME Server.

Moving from Redhat to Centos shouldn’t be difficult, this is already based on Redhat, it isn’t designed with any particular purpose in mind and its not targeted directly at any language or market. So whats not to love? Lance Davis, yes this is 4 years ago, however this will continue to haunt the CentOS project for years to come. The lead developer who controlled not only the domains but the contributions from the community suddenly vanished. The only thing that kept CentOS alive was the community backing. For a corporation to move to this platform you must have significant trust in a community of developers to continue their work for well free. Some business will be more than happy to move to this especially if cost saving measures are being undertaken by the business. Why not save on corporate licensing costs from Redhat when CentOS give you a repackaged product for nothing. This isn’t 100% true, some of the software that is distributed by Redhat is proprietary which you have to purchase licenses from Redhat, however the base system or Redhat is free. For some businesses who have selected Redhat because of their product offerings, IPA or Satallite Server, the move to CentOS may not be as smooth as one expects when these products are suddenly missing from the offerings.

While I’m on the topic of CentOS, what architecture are you trying to migrate from, if your using anything other than x86 or x86_64 your stuck with Redhat or pre V5 releases of Centos. As a project they have decided to concentrate on these two architectures exclusively.

I’m not saying that CentOS isn’t the right choice for corporations, it is one of the few distributions that is a 100% compatible rebuild of RHEL. CentOS is usually targeted at businesses that require the stability and reliability of an enterprise grade product without the often costly support agreements.

ClearOS, for anyone that has been around for a while ClearOS was formally known as Clark Connect. It allowed a small to medium business to insert a DVD boot it up, answer a few questions and magically you had a small business server capable of many different functions that would often take hours if not days to configure and test thoroughly. The primary configuration mechanism for ClearOS is a web interface, again perfect for small to medium business who have the receptionist as their primary system administrator, but for a corporation that is replacing their entire Redhat installation with a distribution that is primarily configured using a web interface ClearOS may not be the most cost effective and easy to manage solution available. The features included range from a simple mail server through to configuration of a stateful packet inspection firewall or MultiWAN configurations. If you are a corporation attempting to replace Redhat how is this useful? This might be if your looking at replacing squid, but with 2000 users your not exactly using DSL for internet connectivity and may be looking for other commercial grade solutions.

Fermi Linux, what the staff at FermiLabs have done and achieved is more than most corporations will every achieve with Linux. Not only have their provided a completely recompiled version of RHEL from source RPMs, but they have continued to modify RHEL for their specific needs. Most corporations will and should avoid using Fermi Linux, not because the distribution isn’t successful or useful, but the need for the modifications performed by FermiLabs may not be suitable for a corporate environment.

Oracle Linux, now there is a can of worms that most people are scared and curious about at the same time. Don’t get me wrong, I’m not attacking Oracle here, their plans to provide a one stop solution for database needs is admirable, however the way in which they have gone about it isn’t the smartest. If your in the market to replace Redhat based Oracle installations and other features that are unique to Oracle Linux then go for it. Features like KSplice and Unbreakable Enterprise Kernel are offering some significant advantages, do you require zero downtime for all your servers, KSplice is your product. It is possible to use almost all offerings from Oracle Linux which are freely available however there is only community support available if your not using Oracle Linux. The biggest catch is Oracle have tailored Oracle Linux for running database servers on their own hardware, in short this may mean it isn’t the most suitable platform to begin building your new infrastructure on.

Rocks Cluster Distribution is primarily used for building High performance computing clusters, clouds and data warehouses. There may be a need for this in many corporations, however this shouldn’t be a one stop replacement. With the latest buzz words flowing left, right and centre all over the internet, corporations want to turn to cloud computing. Unfortunately many are fearful of how to control their data, their intellectual property or even their customer information. RCD allows corporations to build their own internal clouds on their own private networks where they are responsible for and control the access as they need. Moving forward with early development Data Warehousing is supported by RCD, however it should be noted that this is still in a development phase. The potential to provide much of an organisations computing power combined with data storage using a single distribution may in the future attract many different types or organisations to RCD. Its always worth a look if your have exceptionally large data storage needs or require large computing power.

Scientific Linux (SL), FermiLabs & CERN got together and had a child, in the end they decided to call it Scientific Linux. Like all previous variants, SL is still based on RHEL. All packages have been built from source, exactly the same as Fermi Linux, however everyone should take care when selecting SL with the ideals of obtaining a distribution aimed at the scientific community as it doesn’t actually contain any scientific tools, it is only named this in reference to the Labs that jointly collaborated to product the final product. The entire ideal behind SL is to reduce the duplication of effort and provide a stable base product for Labs and Universities to perform experiments with. In a nutshell, SL is a basic version of RHEL with all the bells and whistles removed. Very few extra packages every make it to the base version of SL, some notable packages that do exist in SL are Cluster Suite, Global File System, FUSE, extra filesystems, wireless networking support and IceWM.

SME Server being the final primary distribution that I am going to discuss, this distribution is aimed directly at Small to Medium Enterprises. Again this product is almost identical to ClearOS discussed above, with selected extra’s and minor modifications to support enterprises. If your looking for a single server solution you have likely found it, however most corporations are looking to replace Redhat on multiple servers that range in purposes, if that is your goal, SME Server isn’t for you.

At the end of the day the replacement that is chosen for your organising as based on so many different aspects that I can’t provide you with a summary that simply states Replace RHEL with xyz. Doing this would be irresponsible of me as a professional and at the end of the day is likely to cause issues for your corporation.

What architecture’s do we have?
What software do we currently use?
Can this be replaced easily with the Open Source variant?
Can this be replaced with another product entirely?
What is the purpose of the server?
Does the new selection allow the server to perform the same function?
Can I get support?
Do I need support?
Is community support sufficient?
How different is the new distribution to Redhat?
Do I need to re-write administration scripts?
How much effort is involved?
Will my hardware still work?
How important is patching as soon as the primary provider releases a patch?
These are the types of questions that need to be asked, these are the types of questions you need to be able to answer. If any of these can not be answered, stop immediately. Gaining half an answer isn’t going to solve your problems and is only likely to cause more issues for you in the future.

If I was personally replacing Redhat I would need to understand each and every environment in much greater detail than could possibly be detailed in an email, however most corporations face the same or similar challenges today. Try asking around at the next conference you attend or discussing with your business partners what they use. This could potentially lead you to the right decision.