[sldev] UUID variant/version bits?

[Argent Stonecutter]

On 29-Nov-2007, at 01:39, Zha Ewry wrote:
> Well, in theory.. UUIDs are supposed to be Universal, not domain  
> specific. The bit space is supposed to be big enough... If it  
> isn't, then we'll need to migrate to a bigger one. Zero made the  
> argument on Tuesday, that it *is* big enough. If the bits which are  
> supposed to be used to mark UUID type are enough to push the UUID  
> space too small, then.. we need a bigger bit space.

The thing is that the type fields guarantee that different servers  
can (using MAC addresses for node IDs and UUID version 1, with  
minimal management of the clock sequence within the domain) generate  
UUIDs that do not even potentially overlap, which means that servers  
can perform a probe operation into their UUID space and generate a  
new UUID if they have an internal collision. This means that these  
UUIDs are not just cryptographically unlikely to collide, they're  
actually guaranteed not to collide.