Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-16 Thread Jabbar Azam
I already have thanks. I'll do the tests with the hardware arrives. Thanks Jabbar Azam On 16 April 2013 22:27, aaron morton aa...@thelastpickle.com wrote: Can't we use LCS? Do some reading and some tests… http://www.datastax.com/dev/blog/leveled-compaction-in-apache-cassandra

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-15 Thread Jabbar Azam
I know the SSD's are a bit small but they should be enough for our application. Out test data is 1.6 TB(including replication of rf=3). Can't we use LCS? This will give us more space at the expensive of more I/O but SSD's have loads of I/Os. Thanks Jabbar Azam On 14 April 2013 20:20,

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-14 Thread aaron morton
That's better. The SSD size is a bit small, and be warned that you will want to leave 50Gb to 100GB free to allow room for compaction (using the default size tiered). On the ram side you will want to run about 4GB (assuming cass 1.2) for the JVM the rest can be off heap Cassandra structures.

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-14 Thread Jabbar Azam
Thanks Aaron. Thanks Jabbar Azam On 14 April 2013 19:39, aaron morton aa...@thelastpickle.com wrote: That's better. The SSD size is a bit small, and be warned that you will want to leave 50Gb to 100GB free to allow room for compaction (using the default size tiered). On the ram side

Any experience of 20 node mini-itx cassandra cluster

2013-04-12 Thread Jabbar Azam
Hello, I'm going to be building a 20 node cassandra cluster in one datacentre. The spec of the servers will roughly be dual core Celeron CPU, 256 GB SSD, 16GB RAM and two nics. Has anybody done any performance testing with this setup or have any gotcha's I should be aware of wrt to the

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-12 Thread Colin Blower
If you have not seen it already, checkout the Netflix blog post on their performance testing of AWS SSD instances. http://techblog.netflix.com/2012/07/benchmarking-high-performance-io-with.html My guess, based on very little experience, is that you will be CPU bound. On 04/12/2013 03:05 AM,

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-12 Thread Jabbar Azam
That's my guess. My colleague is still looking at CPU's so I'm hoping he can get quad core CPU's for the servers. Thanks Jabbar Azam On 12 April 2013 16:48, Colin Blower cblo...@barracuda.com wrote: If you have not seen it already, checkout the Netflix blog post on their performance

Re: Any experience of 20 node mini-itx cassandra cluster

2013-04-12 Thread Edward Capriolo
Duel core not the greatest you might run into GC issues before you run out of IO from your ssd devices. Also cassandra has other concurrency settings that are tuned roughly around the number of processors/cores. It is not uncommon to see 4-6 cores of cpu (600 % in top dealing with young gen