[Opensim-dev] Multi-region OAR format

[Justin Clark-Casey]

Robert, I feel that load and save of multiple files simultaneously would be too fragile.  And as Oren said, it ends up 
wasting a lot of space and some processing time for data that is held in common between regions (e.g. assets).

I like this proposal, Oren.  I should have put regions in separate directories originally but it's easy to say that in 
hindsight.  One thing to watch out for is that OpenSimulator has an option to register multiple regions with the same 
name, though I suspect that's not a good idea in many contexts and I can't say for sure whether the option even works. 
So you may have to uniquify region folders with their UUID or similar.

I would also prefer to see regions within a separate regions/ top level folder, e.g. regions/region1, regions/region2, etc.

In the long term I would like to see all OARs to be saved with region directories, including single regions.  However, 
in the interests of forward compatibility for existing OpenSimulator releases I think it is a good idea to save single 
regions in the existing structure, with the multi-region structure only being used with the --all flag.  In a few 
releases time the new format can become the default and the old format only saved with an explicit flag.  Or perhaps one 
could call the new structure .moar (I half kid).

Something I might consider is whether the locations of other directories (e.g. assets) could be specified within the oar 
itself instead of with constants such as ArchiveConstants.ASSETS_PATH, though I don't know if that would help much in 
this case.  Or try and think about ways to make oar/iar loading more liberal in what it accepts (following Postel's 
law).  We used to have the same problem with XML loading where only one order of elements would be accepted but I think 
that has been pretty much eradicated.

On 20/07/12 16:01, Adams, Robert wrote:
> I’m not sure I see the advantage of multiple regions in one oar file. Say I have a 3x3 set of regions saved in a backup
> oar file. I might want to restore one. That necessitates new command line parameters for selection, etc.
>
> To handle multiple regions, another approach is to push the grouping up a level and add commands for loading and
> creating multiple oar files with one command. That keeps the existing oar file format but solve the grouping feature. Or
> how about if the target of a ‘load oar’ is a directory, it loads all of the oar files therein?
>
> -- ra
>
> *From:*opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-bounces at lists.berlios.de] *On Behalf Of *Oren Hurvitz
> *Sent:* Friday, July 20, 2012 6:39 AM
> *To:* opensim-dev at lists.berlios.de
> *Subject:* Re: [Opensim-dev] Multi-region OAR format
>
> On Fri, Jul 20, 2012 at 4:15 PM, Robert L martin [via opensim-dev] <[hidden email]
> </user/SendEmail.jtp?type=node&node=7578166&i=0>> wrote:
>
> okay so if i wanted to make an OAR for "Bad Wolf Island" with a total
> of nine regions it would have
> row 1 (south) Southwest, South center , South East
> row 2 (center) West Center, Center, East Center
> row 3 (north) NorthWest , North Center, North east
>
> and if i wanted to have a 2X4 region then it would be
> row 1 (south) South West , South Center West, South Center East , South East
> row 2 (north) North West, North Center West, North Center East, North East
>
> and any region without data will create a hole in the sim
>
>
> That's right.
>
>     if the server can be made to handle it i would suggest that a "dummy"
>     manifest be used to create "blank" regions (modes would be fixed
>     height, Blend or random)
>
>
> If I understand you correctly, you're asking for the load-oar command to create regions where none existed before. It
> doesn't do that currently, and I don't intend to make it start doing so. There are other ways to create regions (see
> Regions.ini), and I don't intend to add to them as that's a different feature.
>
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> View this message in context: Re: Multi-region OAR format
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-- 
Justin Clark-Casey (justincc)
http://justincc.org/blog
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