On Thu, 22 Feb 2007, Mimi Yin wrote:
While thinking more about the PPC versus Intel Mac scenario, I stumbled over
a Dump and Reload scenario I hadn't previously considered. Upgrading from PPC
to Intel Mac. Here are some questions that came to mind:
1. How do we explain to users that they need to install a different version
of Chandler for Intel Mac?
2. If we succeed in 1, how do we then explain to users that that's not
enough, they need to 'upgrade' their repository too via Dump and Reload.
"Backup and Restore" would work too as long as the schemas are the same.
In that case, it's not an "upgrade", just a port.
3. What if the user has already wiped their old PPC Mac?
They'd restore an older backup :)
If they don't have one, they still have the old PPC repository on their Intel
mac. They can reinstall Chandler on their PPC mac and do a backup there.
4. Even if they haven't committed #3, they've most likely already done the
data transfer thing. If so, how do they get their backup file from their PPC
Mac to their Intel Mac? Can they even locate their backup file? My
understanding was that, that would be opaque to the user.
If they backup their repository in Chandler on PPC using the menus, they
decide where the backup goes. They can then copy that file tree and restore
that repository using the same menus, but this time on Intel.
5. Assuming they can locate and transport the backup file, how do they
restore it on the new Intel Mac?
Using the 'File->Restore..." menu.
Another hurdle: We need to communicate to the user the highly unintuitive
idea that in order to Restore their data on the new Intel Mac, they must
first blow away their old PPC repository, otherwise, Chandler on the new
Intel Mac won't start up at all.)
Not true anymore. With my fix to bug 8186, I put up and dialog informing them
about Backup and Restore. Their chandler should start, but with that error
dialog, and then a fresh repository.
Not to sound panicked or anything, but...Is there a way to do Dump and Reload
for PPC-Intel Mac from the new Intel Mac?
I don't know about "Dump and Reload" but "Backup and Restore" of a PPC
repositoruy on an Intel mac can only work if the PPC bits are run on Intel
which is possible when stubbing out PyLucene (which is not supported under
Rosetta, the PPC emulation on Intel). That PyLucene stub is here [1].
Currently our only 'solution' to this problem is a dialog:
https://bugzilla.osafoundation.org/show_bug.cgi?id=8186
That 'solution' is better than the crash and may be as good as it gets since
we have no control over how and when users copy their stuff around from one
machine to the next.
Any ideas? How important is it for us to get this workflow right?
I should also say that this problem is not specific to PPC -> Intel. Any such
transfer to a different machine is problematic. A Windows user switching to
a Mac would encounter the very same problem.
Berkeley DB environments are not portable, even machine to machine.
The only way to port a repository from one machine to another is via Backup
and Restore. (and via Dump and Reload, once it's implemented, but then
you're not porting your repository, only the latest version of a subset of the
the user's data is getting dumped).
Besides carefully documenting this 'feature', I don't know what else to
suggest.
Andi..
[1] http://svn.osafoundation.org/chandler/trunk/external/PyLucene/dummy/
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