Ok, Raymond i understand. But seems no one have good answer here, it depends on
appropriate fs and near (probably cloud) layer implementation.
If you not observe «throttling» messages (described in prev link) seems it`s
all ok, but of course you can benchmark your io by yourself with 3-rd party
tool.
>Thanks Zhenya.
>
>I have seen the link you provide has a lot of good information on this system.
>But it does not talk about the check point writers in any detail.
>
>I appreciate this cannot be a bottleneck, my question is more related to: "If
>I have more check pointing threads will check points take less time". In our
>case we use AWS EFS so if each checkpoint thread is spending relatively long
>times blocking on write I/O to the persistent store then more check points
>allow more concurrent writes to take place. Of course, if the check point
>threads themselves utilise async I/O tasks and interleave I/O activities on
>that basis then there may not be an opportunity for performance improvement,
>but I am not an expert in the Ignite code base :)
>
>Raymond.
>
>On Wed, Sep 7, 2022 at 7:51 PM Zhenya Stanilovsky via user <
>[email protected] > wrote:
>>
>>No, there is no any log and metrics suggestions and as i told earlier — this
>>place can`t became a bottleneck, if you have any performance problems —
>>describe them somehow wider and interesting reading here [1]
>>
>>[1]
>>https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Persistent+Store+-+under+the+hood
>>
>>>Thanks Zhenya.
>>>
>>>Is there any logging or metrics that would indicate if there was value
>>>increasing the size of this pool?
>>>
>>>
>>>On Fri, 2 Sep 2022 at 8:20 PM, Zhenya Stanilovsky via user <
>>>[email protected] > wrote:
>>>>Hi Raymond
>>>>
>>>>checkpoint threads is responsible for dumping modified pages, so you may
>>>>consider it as io bound only operation and pool size is amount of disc
>>>>writing workers.
>>>>I think that default is enough and no need for raising it, but it also up
>>>>to you.
>>>>
>>>>>Hi,
>>>>>
>>>>>I am looking at our configuration of the Ignite checkpointing system to
>>>>>ensure we have it tuned correctly.
>>>>>
>>>>>There is a checkpointing thread pool defined, which defaults to 4 threads
>>>>>in size. I have not been able to find much of a discussion on when/how
>>>>>this pool size should be changed to reflect the node size Ignite is
>>>>>running on.
>>>>>
>>>>>In our case, we are running 16 core servers with 128 GB RAM with
>>>>>persistence on an NFS storage layer.
>>>>>
>>>>>Given the number of cores, and the relative latency of NFS compared to
>>>>>local SSD, is 4 checkpointing threads appropriate, or are we likely to see
>>>>>better performance if we increased it to 8 (or more)?
>>>>>
>>>>>If there is a discussion related to this a pointer to it would be good
>>>>>(it's not really covered in the performance tuning section).
>>>>>
>>>>>Thanks,
>>>>>Raymond.
>>>>> --
>>>>>
>>>>>Raymond Wilson
>>>>>Trimble Distinguished Engineer, Civil Construction Software (CCS)
>>>>>11 Birmingham Drive | Christchurch, New Zealand
>>>>>[email protected]
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>>
>>
>>
>>
>>
>
> --
>
>Raymond Wilson
>Trimble Distinguished Engineer, Civil Construction Software (CCS)
>11 Birmingham Drive | Christchurch, New Zealand
>[email protected]
>
>
