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From Aaron Morton <aa...@thelastpickle.com>
Subject Re: 4k keyspaces... Maybe we're doing it wrong?
Date Sun, 05 Sep 2010 04:57:04 GMT
Yes, right now it's probably not technically possible, from a resource point of view, to run
4k keyspaces in a cassandra cluster.

Those management features you may have been able to do as meta data operations will prob become
long running background tasks.

Aaron 

On 3 Sep 2010, at 21:28, Mike Peters <cassandra@softwareprojects.com> wrote:

> Very interesting. Thank you
> 
> So it sounds like other than being able to quickly truncate customer-keyspaces, with
Cassandra there's no real benefit in keeping each customer data in a separate keyspace.  
> 
> We'll suffer on the memory side with all the switching between keyspaces and we're better
off storing all customer data under the same keyspace?
> 
> 
> On 9/2/2010 11:29 PM, Aaron Morton wrote:
>> 
>> Create one big happy love in keyspace. Use the key structure to identify the different
clients data. 
>> 
>> The is more support for multi tenancy systems but a lot of the memory configuration
is per keyspace/column family, so you cannot run that many keyspaces. 
>> 
>> This page has some more information http://wiki.apache.org/cassandra/MultiTenant
>> 
>> Aaron
>> 
>> 
>> On 03 Sep, 2010,at 01:25 PM, Mike Peters <cassandra@softwareprojects.com> wrote:
>> 
>>> Hi,
>>> 
>>> We're in the process of migrating 4,000 MySQL client databases to 
>>> Cassandra. All database schemas are identical.
>>> 
>>> With MySQL, we used to provision a separate 'database' per each client, 
>>> to make it easier to shard and move things around.
>>> 
>>> Does it make sense to migrate the 4,000 MySQL databases to 4,000 
>>> keyspaces in Cassandra? Or should we stick with a single keyspace?
>>> 
>>> My concerns are -
>>> #1. Will every single node end up with 4k folders under /cassandra/data/?
>>> 
>>> #2. Performance: Will Cassandra work better with a single keyspace + 
>>> lots of keys, or thousands of keyspaces?
>>> 
>>> -
>>> 
>>> Granted it's 'cleaner' to have a separate keyspace per each client, but 
>>> maybe that's not the best approach with Cassandra.
>>> 
>>> Thoughts?
>> 
> 

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