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From Jabbar Azam <aja...@gmail.com>
Subject Re: Any experience of 20 node mini-itx cassandra cluster
Date Mon, 15 Apr 2013 10:44:08 GMT
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, Jabbar Azam <ajazam@gmail.com> wrote:

> Thanks Aaron.
>
> Thanks
>
> Jabbar Azam
>
>
> On 14 April 2013 19:39, aaron morton <aaron@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 you will want to run about 4GB (assuming cass 1.2) for
>> the JVM the rest can be off heap Cassandra structures. This may not leave
>> too much free space for the os page cache, but SSD may help there.
>>
>> Cheers
>>
>>    -----------------
>> Aaron Morton
>> Freelance Cassandra Consultant
>> New Zealand
>>
>> @aaronmorton
>> http://www.thelastpickle.com
>>
>> On 13/04/2013, at 4:47 PM, Jabbar Azam <ajazam@gmail.com> wrote:
>>
>> What about using quad core athlon x4 740 3.2 GHz with 8gb of ram and
>> 256gb ssds?
>>
>> I know it will depend on our workload but will be better than a dual core
>> CPU. I think....
>>
>> Jabbar Azam
>> On 13 Apr 2013 01:05, "Edward Capriolo" <edlinuxguru@gmail.com> wrote:
>>
>>> 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 garbage managing lots of sockets whatever.
>>>
>>>
>>> On Fri, Apr 12, 2013 at 12:02 PM, Jabbar Azam <ajazam@gmail.com> wrote:
>>>
>>>> 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 <cblower@barracuda.com> wrote:
>>>>
>>>>>  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, Jabbar Azam wrote:
>>>>>
>>>>>   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 hardware?
>>>>>
>>>>>  I do realise the CPU is fairly low computational power but I'm going
>>>>> to assume the system is going to be IO bound hence the RAM and SSD's.
>>>>>
>>>>>
>>>>>  Thanks
>>>>>
>>>>> Jabbar Azam
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>>  *Colin Blower*
>>>>> *Software Engineer*
>>>>> Barracuda Networks Inc.
>>>>> +1 408-342-5576 (o)
>>>>>
>>>>
>>>>
>>>
>>
>

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