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From Ted Dunning <ted.dunn...@gmail.com>
Subject Re: Is it a good idea to embed ZK in a product application ?
Date Tue, 02 Jul 2013 03:37:47 GMT
Embedding zk in a product is a fine thing.  Embedding zk in an application is (in my estimation)
a bad idea.  The problem is that you generally want to coordinate all the way down to zero,
especially in upgrade situations.  Combining the uptime constraints of zk with those of your
app is bad strategy.  

As a concrete example, suppose that you need one or more copy if your software to run and
you are running it on 6 machines.  Should your zk quorum include all 6 machines?  I think
not.  

Now what happens if you want to upgrade?  It is plausible that your app will work with only
or copy running but you probably would want enough to handle current load during a rolling
upgrade.  Should that requirement be combined with the need to preserve a zk quorum?  What
if you have zk on 3 machines and you want to upgrade all three of those in step 1 of a rolling
upgrade.  Do you really want to make that impossible?

Sent from my iPhone

On Jul 1, 2013, at 20:22, Kai Lu <lukai1984@gmail.com> wrote:

> A lot of applications in big companies had done that already.
> 
> On Jul 1, 2013, at 8:06 PM, 吴靖 <qhwj2006@126.com> wrote:
> 
>> Hi all:
>> 
>> 
>>  Recently my company want use zk to manage our cluster( For node management and HA).
But someone in my team want to embed the ZK in our product application.  But somehow I always
feel very odd to embed ZK in.
>>  Here my question are : Is it a  good idea to embed ZK in a product application ?
>>     And dose it work fine  in product mode (like overflow memory and other problems
)?
>> 
>> 
>> 
>> thank you !
>> 
>> 

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