Agree with Ilya that the performance should be comparable if you disable the WAL of the Ignite persistence.
Anyway, the swapping and Ignite persistence pursue different goals. The swapping is one of the out-of-memory protection techniques - if you run out of DRAM, then the OS will start swapping in/out Ignite memory pages to avoid a node outage. But, the swap space is not a durable storage layer. If you restart the cluster, then all the swapped pages will evaporate. While, Ignite persistence is your durable disk tier that survives cluster restarts and, thus, uses more sophisticated algorithms to ensure data consistency and durability. Just select what suits you best. I put more thoughts on this in this article: https://www.gridgain.com/resources/blog/out-of-memory-apache-ignite-cluster-handling-techniques - Denis On Thu, Aug 6, 2020 at 6:23 AM Ilya Kasnacheev <ilya.kasnach...@gmail.com> wrote: > Hello! > > I think the performance of swap space should be on par with persistence > with disabled WAL. > > You can submit suggested updates to the documentation if you like. > > Regards, > -- > Ilya Kasnacheev > > > ср, 5 авг. 2020 г. в 06:00, 38797715 <38797...@qq.com>: > >> Hi Ilya, >> >> If so, there are two ways to implement ignite's swap space: >> 1. maxSize > physical memory, which will use the swap mechanism of the >> OS, can be used *vm.swappiness* Adjust. >> 2. Configure the *swapPath* property, which is implemented by Ignite >> itself, is independent of the OS and has no optimization parameters. >> There's a choice between these two models, right? Then I think there may >> be many problems in the description of the document. I hope you can check >> it again: >> https://apacheignite.readme.io/docs/swap-space >> >> After our initial testing, the performance of swap space is much better >> than native persistence, so I think this pattern is valuable in some >> scenarios. >> 在 2020/8/4 下午10:16, Ilya Kasnacheev 写道: >> >> Hello! >> >> From the docs: >> >> To avoid this situation with the swapping capabilities, you need to : >> >> - Set maxSize = bigger_ than_RAM_size, in which case, the OS will >> take care of the swapping. >> - Enable swapping by setting the DataRegionConfiguration.swapPath >> property. >> >> >> I actually think these are either-or. You should either do the first (and >> configure OS swapping) or the second part. >> >> Having said that, I recommend setting proper Native Persistence instead. >> >> Regards, >> -- >> Ilya Kasnacheev >> >> >> сб, 25 июл. 2020 г. в 04:49, 38797715 <38797...@qq.com>: >> >>> Hi, >>> >>> https://apacheignite.readme.io/docs/swap-space >>> >>> According to the above document, if the physical memory is small, you >>> can solve this problem by opening the swap space,The specific method is to >>> configure maxSize to a larger value (i.e. larger than the physical memory), >>> and the swapPath property needs to be configured. >>> >>> But from the test results, the node is terminated. >>> >>> I think the correct result should be that even if the amount of data >>> exceeds the physical memory, the node should still be able to run normally, >>> but the data is exchanged to the disk. >>> >>> I want to know what parameters affect the behavior of this >>> configuration? *vm.swappiness* or others? >>> 在 2020/7/24 下午9:55, aealexsandrov 写道: >>> >>> Hi, >>> >>> Can you please clarify your expectations? You expected that JVM process will >>> be killed instead of gracefully stopping? What you are going to achieve? >>> >>> BR, >>> Andrei >>> >>> >>> >>> -- >>> Sent from: http://apache-ignite-users.70518.x6.nabble.com/ >>> >>>
