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From Andrei Ivanov <aiva...@iponweb.net>
Subject Re: Compaction Strategy guidance
Date Tue, 25 Nov 2014 12:03:58 GMT
Yep, Marcus, I know. It's mainly a question of cost of those extra x2
disks, you know. Our "final" setup will be more like 30TB, so doubling
it is still some cost. But i guess, we will have to live with it

On Tue, Nov 25, 2014 at 1:26 PM, Marcus Eriksson <krummas@gmail.com> wrote:
> If you are that write-heavy you should definitely go with STCS, LCS
> optimizes for reads by doing more compactions
>
> /Marcus
>
> On Tue, Nov 25, 2014 at 11:22 AM, Andrei Ivanov <aivanov@iponweb.net> wrote:
>>
>> Hi Jean-Armel, Nikolai,
>>
>> 1. Increasing sstable size doesn't work (well, I think, unless we
>> "overscale" - add more nodes than really necessary, which is
>> prohibitive for us in a way). Essentially there is no change.  I gave
>> up and will go for STCS;-(
>> 2. We use 2.0.11 as of now
>> 3. We are running on EC2 c3.8xlarge instances with EBS volumes for data
>> (GP SSD)
>>
>> Jean-Armel, I believe that what you say about many small instances is
>> absolutely true. But, is not good in our case - we write a lot and
>> almost never read what we've written. That is, we want to be able to
>> read everything, but in reality we hardly read 1%, I think. This
>> implies that smaller instances are of no use in terms of read
>> performance for us. And generally nstances/cpu/ram is more expensive
>> than storage. So, we really would like to have instances with large
>> storage.
>>
>> Andrei.
>>
>>
>>
>>
>>
>> On Tue, Nov 25, 2014 at 11:23 AM, Jean-Armel Luce <jaluce06@gmail.com>
>> wrote:
>> > Hi Andrei, Hi Nicolai,
>> >
>> > Which version of C* are you using ?
>> >
>> > There are some recommendations about the max storage per node :
>> >
>> > http://www.datastax.com/dev/blog/performance-improvements-in-cassandra-1-2
>> >
>> > "For 1.0 we recommend 300-500GB. For 1.2 we are looking to be able to
>> > handle
>> > 10x
>> > (3-5TB)".
>> >
>> > I have the feeling that those recommendations are sensitive according
>> > many
>> > criteria such as :
>> > - your hardware
>> > - the compaction strategy
>> > - ...
>> >
>> > It looks that LCS lower those limitations.
>> >
>> > Increasing the size of sstables might help if you have enough CPU and
>> > you
>> > can put more load on your I/O system (@Andrei, I am interested by the
>> > results of your  experimentation about large sstable files)
>> >
>> > From my point of view, there are some usage patterns where it is better
>> > to
>> > have many small servers than a few large servers. Probably, it is better
>> > to
>> > have many small servers if you need LCS for large tables.
>> >
>> > Just my 2 cents.
>> >
>> > Jean-Armel
>> >
>> > 2014-11-24 19:56 GMT+01:00 Robert Coli <rcoli@eventbrite.com>:
>> >>
>> >> On Mon, Nov 24, 2014 at 6:48 AM, Nikolai Grigoriev
>> >> <ngrigoriev@gmail.com>
>> >> wrote:
>> >>>
>> >>> One of the obvious recommendations I have received was to run more
>> >>> than
>> >>> one instance of C* per host. Makes sense - it will reduce the amount
>> >>> of data
>> >>> per node and will make better use of the resources.
>> >>
>> >>
>> >> This is usually a Bad Idea to do in production.
>> >>
>> >> =Rob
>> >>
>> >
>> >
>
>

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