Alex Schuster <[email protected]> [10-09-12 04:13]: > [email protected] writes: > > > I think there is some misunderstanding: > > > > Before migration to 64bit: > > > > /dev/sda3 is mounted on / and contains the 32bit Gentoo > > > > /dev/sda10 is mounted on /home/mcc/migration and will contain the > > stuff of the 64bit Gentoo > > > > After migration I will *not* mount /dev/sda10 on / but will clear all > > stuff from /dev/sda3 and move the contents from /dev/sda10 to > > /dev/sda3. > > > > Is still valid what you said under this premissions, Wonko? > > That's how I understood it, although I assumed the temproary 64bit install > would be on a 2nd drive, thus you would copy it back once it seems to > work. No, I see no problem with this. > > About performance: I'm not sure it will be even noticeable. Yes, most > drives (but not all) are organized so the first partitions go to the > outside, which is faster. With LVM, I used to create two volume groups on > my drive, a group for swap and the system, and another one for data. But > then I thought it's not worth the effort, and I lose some of the LVM > benefits. Well, with everything encrypted I don't get full performance > anyway, so my case might be a little different. > > But the performance increase is only true when reading lots of data. I'm > not sure how big the role of this is in real life. Access time is not > influenced, it will on average take half a turn of the drive till the > heads can access the data, and to me it looks like typical stuff a linux > system does is reading many not so large files, cluttered around in the > file system. But that's my guess only. And I understand that you like to > optimize stuff - I like to do this too. But sometimes I think that the > potential benefit might not be so large, compared to the time I spend > moving data around to the ideal place, or the time I would need to spend > thinking about how to tune things. Or the time you need to fix a problem > that you know was working in the old system, but this is gone now and you > cannot have a quick look at it, or just boot into it. You lose the > opportunity to start your old system in order to compare the times of your > big renderings. And maybe at one point you need to create some true 32bit > applications? Happened to me. So I just chroot into my old system and > build there. > > Oh, and you mentioned databases. Yes, mysql stores itsa data in machine- > depenent form. You will need to dump the data and re-import it in the new > system. You will be happy to still have the 32bit system in such a case :) > > Wonko >
I also cannot evaluate the real impact the position of the /-partition on the harddisk has on system performance. I read about it years ago and since than I always put the partitions always in the sequence of "boot","swap","root","home" onto the harddisks. May be its only a tradition nowadays... ;) Do you know of any other kind of data beside databses, which may be machinedependant or cause trouble while migrating to 64bit? Best regards, mcc
