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Thread: in-place migration from 64-bit to 32-bit

  1. #1

    Default in-place migration from 64-bit to 32-bit

    Hi everybody,

    was wondering if anyone has any advice ("I did it before") re: converting an OpenSUSE 11.1 64-bit machine to a 32-bit one.

    My current machine is a 64-bit 11.1 installation simply because I was "just checking it out" and decided to try a 64-bit OS (this was my first machine with a 64-bit capable CPU - more on this later), thinking that I'd nuke the install later on.

    Funny thing is... I ended up staying on it. I now prefer OpenSUSE to all other linux distros (I used to be an ubuntu man, myself). Now I've got a nicely-set-up 64-bit machine chock full of customizations etc. And I'm running into various little irritations (32-bit stuff more popular/supported). Best of all, because this is a first-gen 64-bit machine, the system chipset can't support more than 3GB of RAM anyways, so there's literally no reason for the machine to be running a 64-bit OS.

    Does anyone have any ideas re: how to do an in-place "migration" from 64-bit to 32-bit? The default option would be to nuke everything other than /home and install, but then there's lots of stuff in /etc and who-knows-where (I've installed things like KeyTouch, etc.) that I'd really like to keep, if possible... (faint hope, I know).

    Anybody?

  2. #2
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    Default Re: in-place migration from 64-bit to 32-bit

    Can't be done in a straightforward way. I'm not even sure you would have much of a chance doing it a crooked way. Word length of the kernel has effects far and wide, in the libraries, in the software. Effectively it's a different arch. Except that... Most 32-bit apps can be got to run under 64-bit by making sure any 32-bit libraries are available. VMWare may be a different can of worms, I have no experience with running that cross-arch.

    If you don't have many customisations installed, just back up your $HOME and reinstall, then restore $HOME.

  3. #3
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    Default Re: in-place migration from 64-bit to 32-bit

    These days I tend to say, there's no reason to run 32bit openSUSE on a 64bit capable machine. Apps without a 64bit version run fine, the real trouble makers like flashplayer and skype are available in 64bit versions through the unofficial channels.
    ° Appreciate my reply? Click the star and let me know why.

    ° Perfection is not gonna happen. No way.

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  4. #4
    Camalen NNTP User

    Default Re: in-place migration from 64-bit to 32-bit

    build6 wrote:

    > Funny thing is... I ended up staying on it. I now prefer OpenSUSE to
    > all other linux distros (I used to be an ubuntu man, myself). Now I've
    > got a nicely-set-up 64-bit machine chock full of customizations etc.
    > And I'm running into various little irritations (for one thing, VMWare
    > won't install right on it). Best of all, because this is a first-gen
    > 64-bit machine, the system chipset can't support more than 3GB of RAM
    > anyways, so there's literally -no reason- for the machine to be running
    > a 64-bit OS.


    Remember that while running a 64-bits OS you can always run 32-bits apps. So
    you can try with VMWare in a 32 bits taste if you are facing some problems
    with its 64 bits counterpart.

    > Does anyone have any ideas re: how to do an in-place "migration" from
    > 64-bit to 32-bit? The default option would be to nuke everything other
    > than /home and install, but then there's lots of stuff in /etc and
    > who-knows-where (I've installed things like KeyTouch, etc.) that I'd
    > really like to keep, if possible... (faint hope, I know).
    >
    > Anybody?


    I think you will have to perform a full reinstall. You can keep your data
    and configurations file, though.

    Greetings,

    --
    Camalen

  5. #5

    Default Re: in-place migration from 64-bit to 32-bit

    hi everyone,

    so far the main real app i've tried that's given me problems is vmware, and I guess that's really because I haven't got the latest version (which has 64 bit support). the tarball for the version I've got won't compile properly (the compilation for the necessary modules always bomb), so, end-result there's some work I can't do on the machine.

    Ultimately, since I am not using >4GB of RAM, there's really no reason for me to use a 64-bit OS, and the tradeoff I feel is not worth it (since I'm gonna be sticking with openSUSE on this machine for a long while :-). It's not just vmware but there are also other problems i've run into here and there. 32-bit OSes are the default, "everybody supports and tests on it" choice so, as a matter of "saving trouble", I want to move there.

    so, no way other than a fresh install, eh? hrm, maybe I should just wait for 11.2 then...

  6. #6
    Camalen NNTP User

    Default Re: in-place migration from 64-bit to 32-bit

    build6 wrote:

    > so far the main real app i've tried that's given me problems is vmware,
    > and I guess that's really because I haven't got the latest version
    > (which has 64 bit support). the tarball for the version I've got won't
    > compile properly (the compilation for the necessary modules always
    > bomb), so, end-result there's some work I can't do on the machine.


    VM compilations are always a bit "picky". You'll need to investigate a bit
    the reason of the failure.

    > Ultimately, since I am not using >4GB of RAM, there's really no reason
    > for me to use a 64-bit OS, and the tradeoff I feel is not worth it
    > (since I'm gonna be sticking with openSUSE on this machine for a long
    > while :-).


    64-bits arch have another advantages besides allowing "big" ram modules :-)

    http://en.wikipedia.org/wiki/64-bit#Pros_and_cons

    > It's not just vmware but there are also other problems i've
    > run into here and there. 32-bit OSes are the default, "everybody
    > supports and tests on it" choice so, as a matter of "saving trouble", I
    > want to move there.


    32-bits OSes will disappear some time. Same happened with 16-bits OSes. The
    only backdraw I see on 64-bits OS right now is they cannot be installed on
    some machines due to processdor limitations, but that's all.

    > so, no way other than a fresh install, eh? hrm, maybe I should just
    > wait for 11.2 then...


    openSUSE 11.2 is due to be released in October/November, I guess.

    Greetings,

    --
    Camalen

  7. #7

    Default Re: in-place migration from 64-bit to 32-bit

    Quote Originally Posted by Camalen View Post
    VM compilations are always a bit "picky". You'll need to investigate a bit
    make bombs in a place I'd never seen it fail before (I'd not had trouble compiling the same thing on other distros - red hat/centos, ubuntu), and I guess I don't have the energy to really dig into it when going 32-bit saves me from not just this but the other small problems here and there as well

    Quote Originally Posted by Camalen View Post
    64-bits arch have another advantages besides allowing "big" ram modules :-)
    right, but "bigmem" is basically the critical factor - if you want more than 4GB, then 32-bit is really not practicable. whereas all the other distinctions are more "you can live without it".

    Quote Originally Posted by Camalen View Post
    32-bits OSes will disappear some time. Same happened with 16-bits OSes. The
    actually i'm not too sure about this. it WILL disappear eventually, but "eventually" can be a very long time away. like how people didn't expect to have to worry about 2 digit date codes, the unix 2038 problem etc. - stuff that works gets left working since you don't want to mess with it. by the time 32 bit OSes are obsolete the capacitors on this machine woulda died a long time ago and I wouldn't be worrying about it either...

    anyways, I think I'm gonna live dangerously and try to see if there's any way to do it like an OS "upgrade"... maybe I'll dive in for a look and if necessary I'll hack the various scripts...

    fingers crossed!

  8. #8
    google01103 NNTP User

    Default Re: in-place migration from 64-bit to 32-bit

    build6 wrote:

    >

    <snip>
    > won't install right on it). Best of all, because

    this is a first-gen
    > 64-bit machine, the system chipset can't support

    more than 3GB of RAM
    > anyways, so there's literally -no reason- for the

    machine to be
    > running a 64-bit OS.
    >

    <snip>
    isn't this a bios issue? On my Asus board I need to
    enable the "memory remapping feature" for more than
    3gb to be seen even though I am running a 64bit OS

    Are you running the latest available bios?

    --
    openSuse 11.1 x64bit, KDE4.x Factory, Opera weekly

  9. #9

    Default Re: in-place migration from 64-bit to 32-bit

    Quote Originally Posted by google01103 View Post
    isn't this a bios issue?
    no it's not. the earlier system chipsets don't support it in hardware, i.e. not just a BIOS settings problem. newer chipsets don't have this problem.

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