[gentoo-user] Install Gentoo on one machine, then move the drive to another

[gentoo-user] Install Gentoo on one machine, then move the drive to another

[Jon M]

Hey again everyone,

Here is my situation:

I have CentOS running on a system in a datacenter, but want to switch to 
Gentoo.  Basically what I've started to do is installed Gentoo on a P4 
3.0Ghz machine at home, and plan on moving it to a Pentium D 2.66Ghz. 
Now if I configure/compile/install all my software on the P4, and the 
kernel is configured for all the hardware in the other machine, will it 
magically work, or will it freak out?  My other concern is that maybe 
the applications won't be optimized for the other machine.  If this is 
the case, once it's down there, could I simply emerge all of my programs 
one at a time?

My reason for doing this is to minimize downtime.  I didn't want to take 
the server offline for a week while I take my time configuring a new 
setup.  This way it should only be down for maybe 5 minutes while I do a 
hard drive swap.

Thanks in advance for anyones thoughts on this.
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Geistteufel]

Well, I do this often time

You can compile on one computer and put the drive to another without any  
problem
If your both computer have the same material ... nothing to do

Well CFGLAS on P4 should be like -02 -march=p4 -pipe -fmoit-frame-pointer
so both are P4, you can switch easyly

if both haven't got same material and you don't use genkernel you should  
probably redo the kernel
if you hd are not at the same place on new computer you need to change  
fstab

but globally, they don't take more than half an hour

good luck

Le Wed, 15 Nov 2006 17:15:35 +0100, Jon M <gentoo@net-xero.net> a écrit:

> Hey again everyone,
>
> Here is my situation:
>
> I have CentOS running on a system in a datacenter, but want to switch to  
> Gentoo.  Basically what I've started to do is installed Gentoo on a P4  
> 3.0Ghz machine at home, and plan on moving it to a Pentium D 2.66Ghz.  
> Now if I configure/compile/install all my software on the P4, and the  
> kernel is configured for all the hardware in the other machine, will it  
> magically work, or will it freak out?  My other concern is that maybe  
> the applications won't be optimized for the other machine.  If this is  
> the case, once it's down there, could I simply emerge all of my programs  
> one at a time?
>
> My reason for doing this is to minimize downtime.  I didn't want to take  
> the server offline for a week while I take my time configuring a new  
> setup.  This way it should only be down for maybe 5 minutes while I do a  
> hard drive swap.
>
> Thanks in advance for anyones thoughts on this.



	

	
		
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Alan McKinnon]

On Wednesday 15 November 2006 18:15, Jon M wrote:
> Hey again everyone,
>
> Here is my situation:
>
> I have CentOS running on a system in a datacenter, but want to switch
> to Gentoo.  Basically what I've started to do is installed Gentoo on
> a P4 3.0Ghz machine at home, and plan on moving it to a Pentium D
> 2.66Ghz. Now if I configure/compile/install all my software on the
> P4, and the kernel is configured for all the hardware in the other
> machine, will it magically work, or will it freak out?  My other
> concern is that maybe the applications won't be optimized for the
> other machine.  If this is the case, once it's down there, could I
> simply emerge all of my programs one at a time?
>
> My reason for doing this is to minimize downtime.  I didn't want to
> take the server offline for a week while I take my time configuring a
> new setup.  This way it should only be down for maybe 5 minutes while
> I do a hard drive swap.
>
> Thanks in advance for anyones thoughts on this.

The one thing you *have* to do is configure the kernel on the compiling 
machine for the correct hardware that the date center machine has. 
There's no magic involved, when you boot into the new machine the 
driver for it's hardware is either there or it isn't.

You probably also want to set your CFLAGS to the lowest common 
denominator cpu - I don't recall off-hand what a Pentium D is, but I 
imagine the setting will be -march=pentium4. This will avoid the 
problem of code being compiled with cpu settings that are not present 
on the target system.

And don't worry too much about optimization. We have a word for that - 
it's called ricing and it's not a good thing. Compile the apps with 
sane settings and stuff works. Trying to eke out those last 4 cpu 
cycles just ain't worth the effort... If you need better performance, 
buy more RAM or faster disks

alan
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Mark M]

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Hi all,
Pentium D is actually an emt64 dual core cpu,
so while CFLAGS -march=pentium4 will work, it will be x86-32 instead of
x86-64 and of course the compiled apps won't know nothing about the dual
core (read almost dual CPU),
still it will run, and it will run fast, you may want to recompile the
kernel on the data center with vSMP option set, so at least the kernel will
know how to manage multithreads between two cores.


On 11/15/06, Alan McKinnon <alan@linuxholdings.co.za> wrote:
>
> On Wednesday 15 November 2006 18:15, Jon M wrote:
> > Hey again everyone,
> >
> > Here is my situation:
> >
> > I have CentOS running on a system in a datacenter, but want to switch
> > to Gentoo.  Basically what I've started to do is installed Gentoo on
> > a P4 3.0Ghz machine at home, and plan on moving it to a Pentium D
> > 2.66Ghz. Now if I configure/compile/install all my software on the
> > P4, and the kernel is configured for all the hardware in the other
> > machine, will it magically work, or will it freak out?  My other
> > concern is that maybe the applications won't be optimized for the
> > other machine.  If this is the case, once it's down there, could I
> > simply emerge all of my programs one at a time?
> >
> > My reason for doing this is to minimize downtime.  I didn't want to
> > take the server offline for a week while I take my time configuring a
> > new setup.  This way it should only be down for maybe 5 minutes while
> > I do a hard drive swap.
> >
> > Thanks in advance for anyones thoughts on this.
>
> The one thing you *have* to do is configure the kernel on the compiling
> machine for the correct hardware that the date center machine has.
> There's no magic involved, when you boot into the new machine the
> driver for it's hardware is either there or it isn't.
>
> You probably also want to set your CFLAGS to the lowest common
> denominator cpu - I don't recall off-hand what a Pentium D is, but I
> imagine the setting will be -march=pentium4. This will avoid the
> problem of code being compiled with cpu settings that are not present
> on the target system.
>
> And don't worry too much about optimization. We have a word for that -
> it's called ricing and it's not a good thing. Compile the apps with
> sane settings and stuff works. Trying to eke out those last 4 cpu
> cycles just ain't worth the effort... If you need better performance,
> buy more RAM or faster disks
>
> alan
> --
> gentoo-user@gentoo.org mailing list
>
>

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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Alan McKinnon]

On Thursday 16 November 2006 01:00, Mark M wrote:
> Hi all,
> Pentium D is actually an emt64 dual core cpu,
> so while CFLAGS -march=pentium4 will work, it will be x86-32 instead
> of x86-64 and of course the compiled apps won't know nothing about
> the dual core (read almost dual CPU),
> still it will run, and it will run fast, you may want to recompile
> the kernel on the data center with vSMP option set, so at least the
> kernel will know how to manage multithreads between two cores.

In that case he should be cross-compiling with a CHOST set for the 
PentiumD, not so?

alan
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Mark M]

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On 11/16/06, Alan McKinnon <alan@linuxholdings.co.za> wrote:
>
> On Thursday 16 November 2006 01:00, Mark M wrote:
> > Hi all,
> > Pentium D is actually an emt64 dual core cpu,
> > so while CFLAGS -march=pentium4 will work, it will be x86-32 instead
> > of x86-64 and of course the compiled apps won't know nothing about
> > the dual core (read almost dual CPU),
> > still it will run, and it will run fast, you may want to recompile
> > the kernel on the data center with vSMP option set, so at least the
> > kernel will know how to manage multithreads between two cores.
>
> In that case he should be cross-compiling with a CHOST set for the
> PentiumD, not so?
>
> alan
> --
> gentoo-user@gentoo.org mailing list
>
>
Yes, he can do so, but he won't be able to test run his apps.
And judging from my experience there isn't much difference between apps
compiled for x86-32 or x86-64, however compiling the kernel for right cpu
speed up things, especially multithreaded.

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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Jon M]

Mark M wrote:
> 
> 
> On 11/16/06, *Alan McKinnon* <alan@linuxholdings.co.za 
> <mailto:alan@linuxholdings.co.za>> wrote:
> 
>     On Thursday 16 November 2006 01:00, Mark M wrote:
>      > Hi all,
>      > Pentium D is actually an emt64 dual core cpu,
>      > so while CFLAGS -march=pentium4 will work, it will be x86-32 instead
>      > of x86-64 and of course the compiled apps won't know nothing about
>      > the dual core (read almost dual CPU),
>      > still it will run, and it will run fast, you may want to recompile
>      > the kernel on the data center with vSMP option set, so at least the
>      > kernel will know how to manage multithreads between two cores.
> 
>     In that case he should be cross-compiling with a CHOST set for the
>     PentiumD, not so?
> 
>     alan
>     --
>     gentoo-user@gentoo.org <mailto:gentoo-user@gentoo.org> mailing list
> 
> 
> Yes, he can do so, but he won't be able to test run his apps.
> And judging from my experience there isn't much difference between apps 
> compiled for x86-32 or x86-64, however compiling the kernel for right 
> cpu speed up things, especially multithreaded.
>  

Hi Mark,

I actually wasn't planning on using 64bit anyway

I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it as 
-march=pentium4?  Are they essentially the same?  I already took your 
previous suggestion and enabled vSMP support, though I haven't moved the 
drive to it's new home as of yet.
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Geistteufel]

Did your actual system install on your Pentium D is in 64 bits ?

Le Thu, 16 Nov 2006 15:45:02 +0100, Jon M <gentoo@net-xero.net> a écrit:

> Mark M wrote:
>>   On 11/16/06, *Alan McKinnon* <alan@linuxholdings.co.za  
>> <mailto:alan@linuxholdings.co.za>> wrote:
>>      On Thursday 16 November 2006 01:00, Mark M wrote:
>>      > Hi all,
>>      > Pentium D is actually an emt64 dual core cpu,
>>      > so while CFLAGS -march=pentium4 will work, it will be x86-32  
>> instead
>>      > of x86-64 and of course the compiled apps won't know nothing  
>> about
>>      > the dual core (read almost dual CPU),
>>      > still it will run, and it will run fast, you may want to  
>> recompile
>>      > the kernel on the data center with vSMP option set, so at least  
>> the
>>      > kernel will know how to manage multithreads between two cores.
>>      In that case he should be cross-compiling with a CHOST set for the
>>     PentiumD, not so?
>>      alan
>>     --
>>     gentoo-user@gentoo.org <mailto:gentoo-user@gentoo.org> mailing list
>>   Yes, he can do so, but he won't be able to test run his apps.
>> And judging from my experience there isn't much difference between apps  
>> compiled for x86-32 or x86-64, however compiling the kernel for right  
>> cpu speed up things, especially multithreaded.
>>
>
> Hi Mark,
>
> I actually wasn't planning on using 64bit anyway
>
> I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it as  
> -march=pentium4?  Are they essentially the same?  I already took your  
> previous suggestion and enabled vSMP support, though I haven't moved the  
> drive to it's new home as of yet.



	

	
		
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Jon M]

Geistteufel wrote:

>> Hi Mark,
>>
>> I actually wasn't planning on using 64bit anyway
>>
>> I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it 
>> as -march=pentium4?  Are they essentially the same?  I already took 
>> your previous suggestion and enabled vSMP support, though I haven't 
>> moved the drive to it's new home as of yet.

 > Did your actual system install on your Pentium D is in 64 bits ?

The OS is installed on a regular Pentium 4 (32bit), but will be 
installed on a Pentium D that can run 64bit, but will be sticking with 
32bit.

Is that what you wanted to know?
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Mark M]

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>
>
> Hi Mark,
>
> I actually wasn't planning on using 64bit anyway
>
> I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it as
> -march=pentium4?  Are they essentially the same?  I already took your
> previous suggestion and enabled vSMP support, though I haven't moved the
> drive to it's new home as of yet.
> --
> gentoo-user@gentoo.org mailing list


x86-32 will be the lowest common settings for all 32bit cpus.
so pentium4 is the setting I believe you should use.
I can tell you from my experience, since I use PentiumD cpu, that
recompiling with -march=prescott gave me better performance then
-marh=x86-32, especially in disk intensive and multimedia applications, such
as video encoding and large database access.

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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Geistteufel]

The system you would replace, is on the Pentium D ? I don't remember the  
distro name, but not the gentoo one.

So if Pentium D contain 64 bits distro you would replace by gentoo ...  
they is a solution to compile it directly on this computer in 64 bits, so  
after just replace the main system with a rescue

If not ... you can copy the system on your pentium 4 ... replace your prod  
for a moment, take the pentium D and install a 64 bits gentoo version ...  
so replace your prod with 64 bits version ... a sort of double switch

you see ?

Le Thu, 16 Nov 2006 16:04:20 +0100, Jon M <gentoo@net-xero.net> a écrit:

> Geistteufel wrote:
>
>>> Hi Mark,
>>>
>>> I actually wasn't planning on using 64bit anyway
>>>
>>> I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it  
>>> as -march=pentium4?  Are they essentially the same?  I already took  
>>> your previous suggestion and enabled vSMP support, though I haven't  
>>> moved the drive to it's new home as of yet.
>
>  > Did your actual system install on your Pentium D is in 64 bits ?
>
> The OS is installed on a regular Pentium 4 (32bit), but will be  
> installed on a Pentium D that can run 64bit, but will be sticking with  
> 32bit.
>
> Is that what you wanted to know?



	

	
		
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Jon M]

Mark M wrote:
> 
>     Hi Mark,
> 
>     I actually wasn't planning on using 64bit anyway
> 
>     I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it as
>     -march=pentium4?  Are they essentially the same?  I already took your
>     previous suggestion and enabled vSMP support, though I haven't moved the
>     drive to it's new home as of yet.
>     --
>     gentoo-user@gentoo.org <mailto:gentoo-user@gentoo.org> mailing list
> 
>  
> x86-32 will be the lowest common settings for all 32bit cpus.
> so pentium4 is the setting I believe you should use.
> I can tell you from my experience, since I use PentiumD cpu, that 
> recompiling with -march=prescott gave me better performance then
> -marh=x86-32, especially in disk intensive and multimedia applications, 
> such as video encoding and large database access.
>  
> 
>  

Hi Mark,

Thanks for the tip!  I'll be sure to switch my CFLAGS to that.  I might 
as well make the system run as fast as it possibly can.

What did you set your MAKEOPTS to?  I was thinking -j3 because of the 
two cores plus one.  Did you do the same?
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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Mark M]

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On 11/16/06, Jon M <gentoo@net-xero.net> wrote:
>
> Mark M wrote:
> >
> >     Hi Mark,
> >
> >     I actually wasn't planning on using 64bit anyway
> >
> >     I'm wondering if I should set my CFLAGS to -march=x86-32 or leave it
> as
> >     -march=pentium4?  Are they essentially the same?  I already took
> your
> >     previous suggestion and enabled vSMP support, though I haven't moved
> the
> >     drive to it's new home as of yet.
> >     --
> >     gentoo-user@gentoo.org <mailto:gentoo-user@gentoo.org> mailing list
> >
> >
> > x86-32 will be the lowest common settings for all 32bit cpus.
> > so pentium4 is the setting I believe you should use.
> > I can tell you from my experience, since I use PentiumD cpu, that
> > recompiling with -march=prescott gave me better performance then
> > -marh=x86-32, especially in disk intensive and multimedia applications,
> > such as video encoding and large database access.
> >
> >
> >
>
> Hi Mark,
>
> Thanks for the tip!  I'll be sure to switch my CFLAGS to that.  I might
> as well make the system run as fast as it possibly can.
>
> What did you set your MAKEOPTS to?  I was thinking -j3 because of the
> two cores plus one.  Did you do the same?
> --
> gentoo-user@gentoo.org mailing list
>
>
yes my MAKEOPTS are -j3 indeed :)

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Re: [gentoo-user] Install Gentoo on one machine, then move the drive to another

[Richard Fish]

On 11/16/06, Jon M <gentoo@net-xero.net> wrote:
> What did you set your MAKEOPTS to?  I was thinking -j3 because of the
> two cores plus one.  Did you do the same?

I suggest MAKEOPTS=-j3 if you have at least 2G of RAM in the box.  If
only 1G, MAKEOPTS=-j2.  If less, -j1.

You can also change this after you move the drive over.

-Richard
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