On 1/25/2016 10:45 AM, Philip Martin wrote:
David Chapman <dcchap...@acm.org> writes:
On 1/25/2016 3:59 AM, Niemann, Hartmut wrote:
I want to upgrade my Linux box from Debian Jessie (32bit) to Debian
Jessie (64bit).
For the transition time, the machine will boot alternating the 32bit
and the 64bit OS.
I have several SVN repositories and working copies on it.
Is it safe to share SVN repositories and working copies between
32bit and 64 bit?
(Jessie ships with 1.8.10, as far as I know.)
It should just work for both repositories and working copies.
Is that documented somewhere, such that system administrators can rely
on it? Or could a Subversion developer decide to put endian- or
size-dependent binary data into a repository or working copy file somewhere?
I wouldn't try this approach for a machine with repositories. I had a
repository on a 64-bit Linux machine, then bought a 32-bit micro
server that I could keep running all the time. I was unable to copy
the repository directory tree directly, even though both were Intel
architecture machines. I had to dump and load (with svnadmin). I'd
be surprised if this has changed in the last three years.
It's hard to work out what went wrong from that vague description. In
the unlikely event that you were using a BDB repository then there are
BDB library compatibility issues: a recover/upgrade may be needed and
downgrading to older BDB is not always possible.
My notes are vague, unfortunately. This was back in 2007, when I was
compiling from tarballs:
1) configure/compile with BDB support on both platforms
2) copy repository directory to 32-bit machine
3) problem found -> dump/load to avoid system dependencies
4) problem solved
5) hey, my repositories are actually FSFS!
I was trying to take good notes, as is my practice for system
administration tasks that I do once every three years, but somewhere in
the migration process I failed to write something down. Item 5) was
recorded some weeks after the migration, so I don't know when the build
switched to FSFS support only, relative to the repository directory
move. Nor do my notes record what actually got me to a
production-worthy repository. So yes, kind of vague. But enough to get
me spooked.
I also know from experience that it is very easy to let platform
dependencies leak into outside data files. Avoidance takes a concerted
effort and detection is extremely difficult when testing a build on a
single machine (here, by definition we're talking about running a single
repository on two separate machines). Thus my question about a
documented promise from Subversion developers.
--
David Chapman dcchap...@acm.org
Chapman Consulting -- San Jose, CA
Software Development Done Right.
www.chapman-consulting-sj.com
