Thanks Ivan, *no less* sounds best for me. Prachi, please do final editing of the doc: https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning
— Denis > On Sep 15, 2017, at 12:24 AM, Ivan Rakov <ivan.glu...@gmail.com> wrote: > > Denis, > > Yes, Ignite page size should be *greater or equal* than OS page cache size > and SSD page size. I mentioned it in advice list: > >> page size of Ignite shouldn't be less than SSD page size >> Page size of Ignite shouldn't be less than OS page size > > Sorry for vague wording. > We should fix this in documentation. > > > Best Regards, > Ivan Rakov > > On 14.09.2017 3:46, Denis Magda wrote: >> Ivan, >> >> Documented: >> https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning >> <https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning> >> >> However, I’m a bit confused with you 6. point regarding the page size >> calculation. Should Ignite page size be always less than the SSD’s page size >> and OS page cache size? Or it can be equal? For instance if the OS page >> cache size is 4 KB what should be Ignite’s page size? That’s the section >> about this: >> https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning#section-page-size >> >> <https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning#section-page-size> >> >> — >> Denis >> >>> On Sep 13, 2017, at 2:29 AM, Ivan Rakov <ivan.glu...@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-architecture-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-provisioning-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 >> >
