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From kannan chandrasekaran <>
Subject Re: Few questions regarding cassandra deployment on windows
Date Wed, 08 Sep 2010 23:39:19 GMT
Thank you. That was helpful.  But as mentioned in the comments section of 
section, the embedded server cannot be shutdown unless the JVM is shutdown due 
to Cassandra's design limitation. Is there a specific reason for this limitation 
? If yes, Can someone please help me understand the reason...


From: Courtney <>
Sent: Tue, September 7, 2010 5:31:46 PM
Subject: Re: Few questions regarding cassandra deployment on windows

I haven't looked at your previos e-mail( s) or the  responses to them but have a 
look at
the post was written by one of the guys who maintains  the hector cassandra 
In any case the simple and short answer is yes, he did  it, so ...

From: kannan chandrasekaran 
Sent: Wednesday, September 08, 2010 1:20 AM
Subject: Re: Few questions regarding cassandra deployment on  windows

Can you  please elaborate on why you think Cassandra would not be suitable for 
this  ?

Main reasons why we think  cassandra because,
1) We are on  focusing on moving to a distributed architecture very soon and 
using cassandra  as a backend naturally lends to this.
2) Our schema is relatively simple and  we wanted quick read and write access. 
Cassandra response times were faster than  Mysql and we expect it to satisfy our 
requirements ( without the need for a  cache layer).
3) I believe with 0.7's live schema updates, the need for  changing the xml 
files and restarting the service would go away. so I believe  usecase2 is only 
difficult in the 0.6 versions... 

I am more interested  in knowing if we can start/run/stop  cassandra as a 
embedded service within  a jvm


 From: Benjamin Black  <>
Sent: Tue, September 7, 2010 4:38:41 PM
Subject: Re: Few questions regarding  cassandra deployment on windows

This does not sound like a good  application for Cassandra at all.  Why
are you using it?

On Tue,  Sep 7, 2010 at 3:42 PM, kannan chandrasekaran
<> wrote:
>  Hi All,
> We are currently considering Cassandra for our  application.
> Platform:
> * a single-node cluster.
>  * windows '08
> * 64-bit jvm
> For the sake of brevity  let,
> Cassandra service =  a single node cassandra server running as  an embedded
> service inside a JVM
> My use  cases:
> 1) Start with a schema ( keyspace and set of column families  under it) in a
> cassandra service
> 2) Need to be able to replicate  the same schema structure (add new
> keyspace/columnfamilies with  different names ofcourse).
> 3) Because of some existing limitations in my  application, I need to be able
> to write to the keyspace/column-families  from a cassandra service and read
> the written changes from a different  cassandra service. Both the write and
> the read "cassandra-services" are  sharing the same Data directory. I
> understand that the application has  to take care of any naming collisions.
> Couple Questions  related to the above mentioned usecases:
> 1) I want to spawn a new JVM  and launch Cassandra as an embedded service
> programatically instead of  using the startup.bat. I would like to know if
> that is possible and any  pointers in that direction would be really helpful.
> ( use-case1)
>  2) I understand that there are provisions for live schema changes in 0.7  (
> thank you guys !!!), but since I cant use a beta version in  production, I am
> restricted to 0.6 for now. Is it possible to to support  use-case 2 in 0.6.5
> ? More specifically, I am planning to make runtime  changes to the
> storage.conf xml file followed by a cassandra service  restart
> 3) Can I switch the data directory at run-time ?  (use-case  3). In order to
> not disrupt read while the writes are in progress, I am  thinking something
> like, copy the existing data-dir into a new location;  write to a new data
> directory; once the write is complete; switch  pointers and restart the
> cassandra service to read from the new  directory to pick up the updated
> changes
> Any help is  greatly appreciated.
> Thanks
>  Kannan

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