Re: [9fans] [plan9mod] Query regarding venti scores

2009-02-06 Thread erik quanstrom
> that doesn't directly address their suitability as UUIDs. it seems > like an odd choice to me (certainly it's an expensive way of > generating them), although i guess it depends what your application > is. sha-1 is a standard uuid format. since a uuid is 16 bytes and sha-1 is 20, there should b

Re: [9fans] [plan9mod] Query regarding venti scores

2009-02-06 Thread Anthony Sorace
the score is the hash of the data in the block. the same block on two servers will have the same score (important for replication). different blocks have the same odds of having this same score (that is, astronomically low) regardless of whether they're on one or multiple servers. that doesn't dir

Re: [9fans] [plan9mod] Query regarding venti scores

2009-02-06 Thread 23hiro
With today's amount of storage the probability of a collision is too low for that to happen. I read that in the Venti paper[1]. I would not consider them UUIDs though, since the same data blocks will have the same sha-1 hash on both servers. If that doesn't cause a problem you're fine [1] http://p

[9fans] [plan9mod] Query regarding venti scores

2009-02-06 Thread anoop . anoop
Hello All, I have a query regarding the scores in venti. Here is my question: Since the venti scores are SHA-1 hashes, can they be considered as UUIDs? I have two different venti servers and am storing different sets of databolcks on each. I am wondering whether a scenario will arise where server