[FAQ] Major Upgrades

[dufeu]

The following is a proposed FAQ to be added to the Gentoo Forums --> Frequently Asked Questions repository. Comments, corrections and suggestions are welcome.

I do know there are some typos present. I'm not particularly worried about those typos at this time. I usually take a couple days off before going back to find and correct simple typos. I'm more interested in areas where I may be mistaken in the information presented or where clarification may be required.

Also, I have gone over the 4 HOW-TO posts I link to for corrections. If more corrections are needed in these HOW-TOs, please let me know.

Best regards to all!





Q: I have a computer running Gentoo which hasn't been updated for a long time. Should I upgrade or re-install Gentoo from scratch?

A: This depends on what the computer in question is used for and how much time you have. In general, consider limited purpose computers such as old computers purposed as routers or servers as good candidates for re-installs and computers individualized with personal data as candidates for upgrading. The reasoning goes like this:

• Impersonal niche computers such as proxy servers, routers, firewalls and other servers contain no personal data and are, at their core, plug and play appliances. Usually, the only customization in these computers are things like firewall, proxy, quality of service and security rules and other items like printer definition, drivers etc.
  
  
• A user's workstation, on the other hand, represents a collection over time of persona data and those programs essential to that user. These user specified programs include customized settings specific for that user. A complete re-install of a user computer must not only re-create their operating system, but must also be re-create their working environment with their customizations and personal data. This is not always easy to do. The longer it's been since the last upgrade of a user computer, the more complex and time consuming it will be.

Q: Is there a Gentoo Sanctioned Major Upgrade Procedure I can run?

A: In a word: No.


Q: Why not?

A: To understand why there isn't a Gentoo Sanctioned Major Upgrade Procedure {herein referenced as GSMUP} the following needs to be clearly understood:

• All GNU/Linux distributions, including Gentoo, consist of collections of independently created, independently maintained and independently updated packages. All these packages were created, maintained and updated by very independent people, groups of people and companies.
  
  
• These packages are tied together only by {mostly} informal conventions and the fact that they run under {in the case of nearly all Gentoo installs} the Linux Kernel. In some areas there are formal standards which are expected to be {voluntarily} followed. These standards include things like where certain types are files are expected to be stored {Linux Standard Base - LSB} and the internal format of binary programs {Executable and Linkable Format - ELF}. Everything else is tied together by accepted voluntary common conventions. Think of the expression: "... like trying to herd cats".
  
  
• A Major Upgrade Procedure {MUP} implies the concept of a monolithic controlling process. In actuality, for any and every computer regardless of operating system {OS}, there is no such thing as a MUP. Instead, the OS is updated first. Then various software packages are individually updated one at a time.
  
  
• By definition, since there cannot be a MUP, there cannot be a GSMUP. And indeed, no general purpose GNU/Linux distribution, Unix, Windows or OSX installation has or supports a true MUP. Once any software beyond the base of the OS is installed, every upgrade process performed for that OS is done piecemeal.
  
  
• The concept of Portage assumes that the designated PC administrator is running "emerge --sync && emerge -uND world" on some regular, relatively short periodic basis. If this assumption is true, then there is no need for a GSMUP.

Q: What about Apple's OSX? You claim they don't have a MUP.

A: Correct. I did mention Apple's OSX. The moment that any third party software package is installed, by definition, that third party package is not and cannot be part of Apple's next upgrade release. i.e. You need to upgrade OSX and then any installed third party apps separately, one app at a time.


Q: What about Redhat? {or other GNU/Linux distribution}

A: In these cases, only a select subgroup of packages are included in each of these respective distros' MUPs. All packages outside of these subgroups must be upgraded separately, one app at a time.


Q: But what about Ubuntu? I've heard that you can upgrade across major release numbers.

A: There is Ubuntu Community guidance for performing upgrades from one animal level to another. i.e. 8.10 to 9.04. However, the instructions for these invariably state: "This procedure is unsupported!", "Do at your own risk!", "Do not enter a bug report if this procedure fails!", "Back up all your data first!". "Not recommended!!!" Like Gentoo and all other distributions, Ubuntu has the same issue of potential conflicts between various packages and their respective installed release levels. If you strictly adhere to and install only packages actively supported by Ubuntu, you might be able to perform a single Ubuntu major level upgrade on an existing Ubuntu install. And by the way, don't call us if it fails.


Q: Oh-kaayyy. Is it even possible to perform a MUP on a Gentoo Install?

A: In a word: YES.


Q: So what do I need to know before I start?

A: These are some good things to know/have before you take on a Gentoo Major Upgrade {GMU}.

• You need some familiarity with running portage.
  
• Understanding how to resolving issues like "blockers" and "masked packages" is invaluable.
  
• Patience. Patience. Patience.
  
• Understanding that a GMU is nothing more than a regular "emerge --sync && emerge -uND world" writ large. The difference between a regular emerge and a GMU is when you do a GMU, you need to help emerge along with what it needs to do.
  

Q: Is there a procedure I can follow to perform a GMU?

A: In a word: YES. There are a series of HOW-TOs that have been written expressly to demonstrate how to perform a Gentoo Major Upgrade. These HOW-TOs have been broken down into logical portions. They cover the steps, reasons for those steps and take an actual PC through the entire process. These HOW-TOs can be found:

• HOWTO: Major System Upgrades - Post I - Preparation - This HOW-TO discusses the initial preparation required for doing a GMU. Preparation includes cleaning out unneeded packages, cleaning out packages which might interfere with an upgrade, tools to add to aid the upgrade process and preparation for using the Command Line Interface {CLI}. It also includes further discussion of why you might want to perform GMU versus a re-install.
  
  
• HOWTO: Major System Upgrades - Post II - Initial Upgrades ++ - This HOW-TO discusses the initial upgrades that need to be performed first and second. It also discusses cleaning out more unneeded or undesirable packages and some general discussion about updating the kernel.
  
  
• HOWTO: Major System Upgrades - Post III - World Domination - This HOW-TO covers the "emerge -uND @world" process. It includes examples of interruptions of that process and how to fix them. It also includes the immediate follow-on steps required after "emerge -uND @world" completes.
  
  
• HOWTO: Major System Upgrades - Post Mortem - This HOW-TO discusses more cleaning up that may be needed after a GMU and provides an informal list of items to check for/steps to perform before declaring the GMU to be complete.
  

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