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From Nikita Ivanov <nivano...@gmail.com>
Subject Re: Durable Memory and Ignite Persistence Tuning
Date Wed, 13 Sep 2017 09:54:59 GMT
Excellent work on this... This should be expanded and be prominently placed
in our docs/tutorials/javadocs/etc.

Nikita Ivanov

On Wed, Sep 13, 2017 at 12:29 PM, Ivan Rakov <ivan.glukos@gmail.com> wrote:

> Folks,
> We had some experience of benchmarking Ignite with persistent store on
> SSD. I think we can share some helpful advice. None of them require
> changing configuration of Ignite or persistent store.
> *Tuning advice for users*
> 1) Be prepared for LFS performance decrease after several hours of
> intensive load. Unfortunately, that's how SSD drives work:
> http://codecapsule.com/2014/02/12/coding-for-ssds-part-2-arc
> hitecture-of-an-ssd-and-benchmarking/
> Consider buying fast production-level SSD drives.
> 2) Consider using separate drives for LFS files and WAL. Ignite actively
> performs writes to both LFS and WAL under intensive load, and having two
> devices will double your throughput limit.
> 3) Over-provision your SSD. Performance of random writes on 50% filled
> disk is much better than on 90% filled. SSD Over-Provisioning And Its
> Benefits: http://www.seagate.com/ru/ru/tech-insights/ssd-over-provisio
> ning-benefits-master-ti/
> 4) Leave free space in RAM to let OS use page cache and optimize writes.
> Total size of all memory policies shouldn't exceed 70% of your RAM.
> 5) Make sure that OS doesn't utilize swap. If you use Unix, best option is
> set vm.swappiness to 0.
> 6) Try to find out page size of your SSD. Ideally, page size of Ignite
> shouldn't be less than SSD page size. Possible approaches:
> Find it in device specification (some manufacturers don't reveal it)
> Try running SSD benchmarks
> If you are not sure, just set page size to 4K. As various benchmarks use
> 4K pages, manufacturers have to adapt drives for 4K random write workload.
> Whitepaper from Intel showing that 4K pages are enough:
> https://www.intel.com/content/dam/www/public/us/en/documents
> /white-papers/ssd-server-storage-applications-paper.pdf
> Check your OS page cache size. Page size of Ignite shouldn't be less than
> OS page size. How to check OS cache page size in Unix:
> https://unix.stackexchange.com/questions/128213/how-is-page-
> size-determined-in-virtual-address-space
> Best Regards,
> Ivan Rakov
> On 01.09.2017 21:08, Denis Magda wrote:
>> Igniters,
>> I see a lot of complains regarding the performance of the subj on the
>> user list. At the same time, I do believe that in most scenarios it’s a
>> lack of knowledge that we keep in secret.
>> It's time to document Durable Memory and its Native Persistence tuning
>> parameters. Let's start doing this for Linux based deployments first. Here
>> is what we have for now (which is almost nothing):
>> https://apacheignite.readme.io/docs/durable-memory-tuning <
>> https://apacheignite.readme.io/docs/durable-memory-tuning>
>> Ideally, at some point we have to come up with doc like this:
>> https://access.redhat.com/sites/default/files/attachments/
>> deploying-oracle-12c-on-rhel6_1.2_1.pdf
>> Please share your expertise in a form of settings that have to be put on
>> the paper. We put them in JIRA and document afterwords:
>> https://issues.apache.org/jira/browse/IGNITE-6246 <
>> https://issues.apache.org/jira/browse/IGNITE-6246>
>> —
>> Denis

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