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From Denis Magda <dma...@apache.org>
Subject Re: Data region's data page size
Date Tue, 07 Nov 2017 19:34:55 GMT
Yes, you should if average object size exceeds 4KB because otherwise Ignite will spend more
time spreading and maintaining a single object across several pages. 


> On Nov 7, 2017, at 11:14 AM, Andrey Kornev <andrewkornev@hotmail.com> wrote:
> Thanks Ivan! A follow-up question, if you don't mind. 
> Should I consider changing the default 4K page size to 8K (or possibly to 16K) if the
average size of my cache objects is, say, 12K, with max size up to 100K?
> Thanks
> Andrey
> From: Ivan Rakov <ivan.glukos@gmail.com>
> Sent: Tuesday, November 7, 2017 8:22 AM
> To: user@ignite.apache.org
> Subject: Re: Data region's data page size
> Hello Andrey,
> Short answer: just keep default 4k page size, it will work fine unless you have very
specific hardware.
> Too small page size causes write amplification on hardware level: https://www.cactus-tech.com/resources/blog/details/write-amplification-as-seen-in-solid-state-drives
> On the other hand, too big page size causes write amplification on Ignite level. Whole
16k page will be persisted if you have changed only few bytes.
> You may also want to check our durable memory tuning guide for more details:https://apacheignite.readme.io/docs/durable-memory-tuning
> Best Regards,
> Ivan Rakov
> On 07.11.2017 1:28, Andrey Kornev wrote:
>> Hello,
>> What are the considerations for choosing the best data page size? It looks like there
are only four possible values (1K, 4K, 8K and 16K) to choose from, and I don't immediately
see why one would want to use anything other than 16K?
>> Is it because the value lookup within a page is linear and therefore, I want to keep
the number of values that fit on a single page sufficiently low?
>> Please advise!
>> Thanks
>> Andrey

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