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Date: Wed, 25 Jan 2012 11:26:00 +0200
From: Ioan Eugen Stan <stan.ieugen@gmail.com>
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To: user@zookeeper.apache.org, eric.charles@u-mangate.com,
 norman@apache.org
Subject: building an distribuited mail-store UID generator using zookeeper
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Hello,

I'm pretty new to Zk and I wish to design a distribuited uid generator 
with it. I'm working on Apache James (email server) and we have a HBase 
Mailbox implementation but we are missing this piece to go closer to 
full distributed mail store.

The problem:

Each message in the mail-store has a unique UID that is 32 bits long. 
They all have to be unique for one mailbox and must be (generated) in 
ascending order. It's similar to the sequence znode type available in Zk.

A new UID is required for every new email, moved email, and some other 
operations.

I wish to store uid's for mailboxes as ZK paths:
/m/${mailbox-uuid-or-name}/uid-


My question is if Zookeeper can support a huge amount of sequence znodes 
in the range of let's say 15 milion and do update on a fraction of those.

Thanks,

-- 
Ioan Eugen Stan
http://ieugen.blogspot.com