On Mon, 21 Sep 2009, Nick Holland wrote:

David Vasek wrote:

From http://www.openbsd.org/faq/faq12.html#amd64better :

12.3.3 - Is it always better to run OpenBSD/amd64 on processors that
         support it?

   Not always.

    There are a number of reasons one may desire to use OpenBSD/i386 over
    OpenBSD/amd64, even on hardware that supports amd64 code:
[...]
    * Need for ability to move disks to another machine that isn't amd64
      capable
[...]

Do I understand it right that disks (FFS, disklabel?) from OpenBSD/i386 cannot be accessed on OpenBSD/amd64 or vice versa?

ACCESSED, yes, you can access data on your amd64 disks on an i386 system.

That sentence was intended to refer to repair. If your amd64 system craps out and you need to pull the disks out and put it in another machine and have it Just Work (or work with minimal effort), you need to have another amd64-compatible processor. That wasn't referring to a file system issue, but rather a rapid repair issue.

I see, it refers to something else. It's clear now. May I suggest a slight modification to that sentence in the FAQ then?

    * Need for ability to move disks with already installed
      operating system to another machine that isn't amd64 capable


Best way I know of to back up a lot of odd machines is to one store is running your favorite backup application so it dumps its data over ssh link to the one machine (which you have a spare of for repair purposes) which has the backup media attached to it.

I agree, this is approximately what I am doing, but sometimes a directly connected USB-attached disk comes handy.

however, if "Different architectures" means amd64 and i386, no issues at all.

Yes, i386 and amd64 currently, but I would like to stay compatible with sparc64 too. However, sparc64 is big-endian so I am out of luck anyway. And "foreign" filesystems (ext2fs) are so slow on OpenBSD.

Thanks, Nick.

Regards,
David

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