Re: Zookeeper instead of CLD in Hail

[Jeff Garzik <jeff@garzik.org>]

On 06/04/2010 11:27 PM, Pete Zaitcev wrote:
> I heard people say they cribbed from the same Chubby paper, but
> it's bollocks. It's absolutely nothing like what Chubby implies.
> No locks for one thing. To be sure, Zookeeper provides a canned
> piece of code which implements locks, kinda like you can implement
> compare-and-swap using Dekker's algorithm on a CPU that doesn't
> have it. The canned lock creates "sequenced" files (using a ZK
> server call that creates unique filenames), then sets some
> "watches" (same as CLD offers), then re-reads the directory to
> find the lowest number sequential file, which is the winner of
> the lock. Haha, only serious. I tested it, it works, but ewwwww.

Yeah, the main similarity is...  both ZK and CLD offer some type of 
filesystem (with all that implies).  ZK is IMO not much like Chubby at 
all, in terms of focus / design goals.

	Jeff