This issue has to be looked from a micro and macro level. On the microlevel the "best" way is workload specific. On the macro level this mostly boils down to data and memory size.

Companions are going to churn cache, this is unavoidable. Imho solid state makes the micro optimization meanless in the big picture. Not that we should not consider tweaking flags but just saying it is hard to believe anything like that is a game change.

On Monday, December 10, 2012, Rob Coli <rcoli@palominodb.com> wrote:
> On Thu, Dec 6, 2012 at 7:36 PM, aaron morton <aaron@thelastpickle.com> wrote:
>> So for memory mapped files, compaction can do a madvise SEQUENTIAL instead
>> of current DONTNEED flag after detecting appropriate OS versions. Will this
>> help?
>>
>>
>> AFAIK Compaction does use memory mapped file access.
>
> The history :
>
> https://issues.apache.org/jira/browse/CASSANDRA-1470
>
> =Rob
>
> --
> =Robert Coli
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>