Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
32bit -> 64bit without downtime
View unanswered posts
View posts from last 24 hours

 
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64
View previous topic :: View next topic  
Author Message
kolcon
Tux's lil' helper
Tux's lil' helper


Joined: 21 Sep 2007
Posts: 93
Location: Europe, CZ

PostPosted: Sun Aug 08, 2010 8:50 pm    Post subject: 32bit -> 64bit without downtime Reply with quote

Hello,

I have a server currently running 32bit Gentoo.
Say I would like to migrate it to 64bit (the CPU is capable of it).

Is it possible to do a chroot install? I would like to minimize the downtime.
Or - perhaps - somehow - compile 64bit kernel, reboot (minimal downtime) and then
continue building the chroot?

Thank you

Lubos
Back to top
View user's profile Send private message
NeddySeagoon
Administrator
Administrator


Joined: 05 Jul 2003
Posts: 32018
Location: 56N 3W

PostPosted: Sun Aug 08, 2010 9:00 pm    Post subject: Reply with quote

kolcon,

You can't do a 64 bit chroot install while you run a 32 bit kernel.

You also need to swap your toolchain in one go. A mix of 32 bit and 64 bit is horribly broken.
Lastly, the /lib layout is different as 64 bit installs have some 32 bit libs, so they can run 32 bit software.

It will be much less pain, and probably faster, to reinstall
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.
Back to top
View user's profile Send private message
kolcon
Tux's lil' helper
Tux's lil' helper


Joined: 21 Sep 2007
Posts: 93
Location: Europe, CZ

PostPosted: Mon Aug 09, 2010 10:43 am    Post subject: Reply with quote

NeddySeagoon wrote:
kolcon,

You can't do a 64 bit chroot install while you run a 32 bit kernel.

You also need to swap your toolchain in one go. A mix of 32 bit and 64 bit is horribly broken.
Lastly, the /lib layout is different as 64 bit installs have some 32 bit libs, so they can run 32 bit software.

It will be much less pain, and probably faster, to reinstall


OK, I understand. I will postpone the migration to 64bit then, as it would probably not give
any real benefits anyway. Will just wait for new machine and then do it clean.
Back to top
View user's profile Send private message
neuron
Advocate
Advocate


Joined: 28 May 2002
Posts: 2371

PostPosted: Sun Sep 05, 2010 4:20 pm    Post subject: Reply with quote

You can probably setup a generic 64bit build in a virtual machine and move that over afterwards. Then rebuild the system with the right cflags after.
Back to top
View user's profile Send private message
chithanh
Developer
Developer


Joined: 05 Aug 2006
Posts: 1668
Location: Berlin, Germany

PostPosted: Sun Sep 05, 2010 6:40 pm    Post subject: Reply with quote

It is possible with minimal downtime if your kernel supports kexec(). But it requires some preparation. Basically the steps are as follows:
  1. Install a 64 bit kernel using crossdev or similar
  2. kexec() to your 64 bit kernel
  3. Build a 64 bit system in chroot
  4. Switch to your new system using busybox switch_root
Steps 2 and 4 need to be done from single user mode. Probably it would be a good idea to exercise all steps in a test environment before applying to a production system.
Back to top
View user's profile Send private message
Corona688
Veteran
Veteran


Joined: 10 Jan 2004
Posts: 1204

PostPosted: Fri Sep 10, 2010 3:44 am    Post subject: Reply with quote

kolcon wrote:
OK, I understand. I will postpone the migration to 64bit then, as it would probably not give
any real benefits anyway. Will just wait for new machine and then do it clean.
I had to sneakernet a disk home recently to fsck it, the 32-bit machine couldn't do so without running out of virtual memory.
_________________
Petition for Better 64-bit ATI Drivers - Sign Here
http://www.petitiononline.com/atipet/petition.html
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Gentoo on AMD64 All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum