Read IOPS are higher than write when all we are doing is write

[KR Kumar <kr...@gmail.com>]

Hi - I have a simple cache object which has a signature of <Long, byte[]>
and I am writing events through streamer. Though it's just a write
operation throughout the test, After sometime, read IOPS have gone
significantly higher and they are actually greater than write IOPS. So my
question is what ignite reading and why it's reading anything when all I am
doing is writing data to ignite. Ignite native persistence is enabled and
the disk that I am using is gp2 at 16000 IOPS in AWS environment. Any
pointers??

Here is the visual snapshot of the IOPS on one of the servers:

[image: read-iops.png]

Thanx and Regards,
KR Kumar

Re: Read IOPS are higher than write when all we are doing is write

[Vladislav Pyatkov <vl...@gmail.com>]

Yes, it can be. More over, indexes pages also will be able to be evicted
and after it will be required to return them for updating when insert a new
entry.

On Sat, Sep 5, 2020 at 6:39 PM krkumar24061975@gmail.com <
krkumar24061975@gmail.com> wrote:

> Hi Vlad - Thanks for the response.
>
> In this test, we write once and no reads/updates throughout the process.
> Would that still result into reading of pages. Also, are you telling that
> Ignite writes/evicts half filled pages to disk and read them back later
> when
> you have to append a key/value to the page??
>
> Thanx and Regards,
> KR Kumar
>
>
>
> --
> Sent from: http://apache-ignite-users.70518.x6.nabble.com/
>


-- 
Vladislav Pyatkov

Re: Read IOPS are higher than write when all we are doing is write

["krkumar24061975@gmail.com" <kr...@gmail.com>]

Hi Vlad - Thanks for the response. 

In this test, we write once and no reads/updates throughout the process.
Would that still result into reading of pages. Also, are you telling that
Ignite writes/evicts half filled pages to disk and read them back later when
you have to append a key/value to the page??

Thanx and Regards,
KR Kumar



--
Sent from: http://apache-ignite-users.70518.x6.nabble.com/

Re: Read IOPS are higher than write when all we are doing is write

[Vladislav Pyatkov <vl...@gmail.com>]

Hi,

After region capacity exhausted (DataRegionConfiguration#setMaxSize) a page
replacement is started.
There is a read-load from reading the pages from a disc, when you update
some key or try to write into evicted page was not fully filled.

On Fri, Sep 4, 2020 at 5:55 PM KR Kumar <kr...@gmail.com> wrote:

> Hi - I have a simple cache object which has a signature of <Long, byte[]>
> and I am writing events through streamer. Though it's just a write
> operation throughout the test, After sometime, read IOPS have gone
> significantly higher and they are actually greater than write IOPS. So my
> question is what ignite reading and why it's reading anything when all I am
> doing is writing data to ignite. Ignite native persistence is enabled and
> the disk that I am using is gp2 at 16000 IOPS in AWS environment. Any
> pointers??
>
> Here is the visual snapshot of the IOPS on one of the servers:
>
> [image: read-iops.png]
>
> Thanx and Regards,
> KR Kumar
>


-- 
Vladislav Pyatkov