Igniters, The first version of the guide is ready. Please check it up before it’s shared with the users: https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning
*Ivan*, please clarify this: - Should Ignite page size be always less than the SSD’s page size and OS page cache size? Or it can be *equal* as well? For instance if the OS page cache size is 4 KB what should be Ignite’s page size? I would set 4 which is not less! Check this paragraph here [1] - It’s said that Intel confirm 4 KB should be enough if you can’t sort out SSD page size value and you give this link [2]. Please point out to the page where this is stated. [1] https://apacheignite.readme.io/v2.1/docs/durable-memory-tuning#section-page-size [2] https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/ssd-server-storage-applications-paper.pdf — Denis > On Sep 13, 2017, at 5:46 PM, Denis Magda <dma...@apache.org> 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 >> >
