[Opensim-dev] Always mutable assets in OpenSim -- does it make sense?

[Melanie]

That is why it needs to be optional. I would never want it for my grid.

Melanie


Frisby, Adam wrote:
> Be careful here however,
> 
> Because if the hashing algorithm you choose ever gets 'broken' where it's possible to calculate a binary against a desired result, then people can potentially overwrite existing assets, etc.  A long hash tends to act as a good barrier against this. (256bit+ is ideal.)
> 
> Regards,
> 
> Adam
> 
> From: opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-bounces at lists.berlios.de] On Behalf Of Stefan Andersson
> Sent: Wednesday, 17 December 2008 12:59 AM
> To: opensim-dev at lists.berlios.de
> Subject: Re: [Opensim-dev] Always mutable assets in OpenSim -- does it make sense?
> 
> First step would probably be to implement the sha-based binary store that you bring up and that we've discussed earlier, so that the immutables at least share the same binary data row. Right now, I believe we're seing massive duplication when people export/import content between worlds. Storing the binaries separately by sha key would probably be an low hanging fruit.
> 
> I would say that it's probably very much up to the service (aka 'the grid') how assets should be managed. On an grid that employs a consumer/producer division (like a fantasy game) you could probably reap dead assets quite aggressively. In a SL business model, it becomes harder, as they have to ensure consistent user experience in a heterogenous environment.
> 
> Best regards,
> Stefan Andersson
> Tribal Media AB
> 
>> Date: Sun, 14 Dec 2008 14:48:01 +0900
>> From: mmazur at gmail.com
>> To: opensim-dev at lists.berlios.de
>> Subject: [Opensim-dev] Always mutable assets in OpenSim -- does it make sense?
>>
>> Hi,
>>
>> Melanie's recent thread[1] on updating assets prompted me to put in
>> writing some thoughts on this topic I've been having.
>>
>> I'm curious whether it may be beneficial to make assets mutable. AFAIK
>> assets are currently immutable because of a LL decisions early on to
>> re-use one asset instance for very popular items sold no-modify. This
>> makes sense for them because they can:
>>
>> * clean up unused assets since they own the entire infrastructure
>> (regions & DBs)
>> * save on space because they anticipate more identical copies rather
>> than slightly modified copies
>>
>> Perhaps taking the opposite approach in OpenSim would be a better fit?
>> I mean, copying assets when they are transferred between owners, and
>> modifying them if they are modified in-world. I can see a few reasons
>> this might be beneficial:
>>
>> * OpenSim's databases are distributed so cleaning them (reaping dead
>> assets) is more difficult
>> * with the advent of distributed asset servers and the long-term
>> vision of a wide open 3D Internet (like HyperGrid), when an item is
>> transferred in-world its assets should probably be stored in that
>> avatar's own inventory DB *anyway*
>> * disk is cheap, and I wonder which is more wasteful -- multiple
>> copies of an asset, each differing slightly due to minor edits over
>> time, or multiple copies of identical assets because they correspond
>> to different objects in-world
>>
>> I see this as a cleaner approach to assets for the future. Sure,
>> storing duplicate identical assets in a DB can be wasteful, but this
>> could be alleviated with hashes of the asset or whatnot (I believe
>> this was brought up on this list before).
>>
>> I realize this change would mean deep, possibly breaking, changes
>> throughout the source code, would take a long time to hash out, etc. I
>> thought I'd throw it out there anyway.
>>
>> Your thoughts -- or perhaps clarifications on why this absolutely
>> cannot be done -- appreciated :)
>>
>> Thanks,
>> Mike
>>
>> [1] https://lists.berlios.de/pipermail/opensim-dev/2008-December/004025.html
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> 
> 
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