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 > http://www.datastax.com/dev/blog/when-to-use-leveled-compaction > > Cheers > > ----------------- > Aaron Morton > Freelance Cassandra Consultant > New Zealand > > @aaronmorton > http://www.thelastpickle.com > > On 15/04/2013, at 10:44 PM, Jabbar Azam <aja...@gmail.com> wrote: > > 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 <aja...@gmail.com> wrote: > >> 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 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 <aja...@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" <edlinuxg...@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 <aja...@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 <cblo...@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) >>>>>> >>>>> >>>>> >>>> >>> >> > >
