Repository: ignite Updated Branches: refs/heads/ignite-10639 [created] a8da9d8f3
IGNITE-10639 Proof of concept for internal description for packages Project: http://git-wip-us.apache.org/repos/asf/ignite/repo Commit: http://git-wip-us.apache.org/repos/asf/ignite/commit/a8da9d8f Tree: http://git-wip-us.apache.org/repos/asf/ignite/tree/a8da9d8f Diff: http://git-wip-us.apache.org/repos/asf/ignite/diff/a8da9d8f Branch: refs/heads/ignite-10639 Commit: a8da9d8f358ff4ef7d2f7e410a173bcee81e82b6 Parents: 5f9a1e6 Author: Dmitriy Pavlov <[email protected]> Authored: Tue Dec 11 13:31:11 2018 +0300 Committer: Dmitriy Pavlov <[email protected]> Committed: Tue Dec 11 13:31:11 2018 +0300 ---------------------------------------------------------------------- modules/direct-io/src/README.md | 57 ++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/ignite/blob/a8da9d8f/modules/direct-io/src/README.md ---------------------------------------------------------------------- diff --git a/modules/direct-io/src/README.md b/modules/direct-io/src/README.md new file mode 100644 index 0000000..38f747f --- /dev/null +++ b/modules/direct-io/src/README.md @@ -0,0 +1,57 @@ +Apache Ignite Direct IO Module +------------------------------ + +Apache Ignite Direct IO is plugin, which provides page store with ability to write and read cache partitions +in O_DIRECT mode. + + +OS gets the data and stores it in a file buffer cache (Page Cache). + +<img src="https://docs.google.com/drawings/d/e/2PACX-1vQBR0OoKFeQ1AOMyDK9QoQEBLDs4kbs7EY6Ed48HnRjlM0J1Ao3g_glD7AR3KZRtUcAVL6hQut6IPVw/pub?w=638&h=499";> + +Similarly, for every write operation, +the OS first writes the data in a cache and then transfers to the disk. To eliminate this process you can enable +Direct I/O in which case the data is read and written directly from/to the disk bypassing the file buffer cache. + +Direct I/O plugin in Ignite is used for the checkpointing process where the dirty pages in RAM are written to the disk. + +Importing Direct I/O Pluging In Maven Project +------------------------------------- + +If you are using Maven to manage dependencies of your project, you can add Direct IO Module +dependency like this (replace '${ignite.version}' with actual Ignite version you are +interested in): + +```xml +<project xmlns="http://maven.apache.org/POM/4.0.0"; + xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; + xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 + http://maven.apache.org/xsd/maven-4.0.0.xsd";> + ... + <dependencies> + ... + <dependency> + <groupId>org.apache.ignite</groupId> + <artifactId>ignite-direct-io</artifactId> + <version>${ignite.version}</version> + </dependency> + ... + </dependencies> + ... +</project> +``` + +Importing Direct I/O Pluging In Gradle Project +------------------------------------- +For gradle you can add compile dependency, where igniteVersion is actual Ignite version: + +compile group: 'org.apache.ignite', name: 'ignite-direct-io', version: igniteVersion + +Additional setup is not required. Once plugin is available in classpath, it will be used for Durable Memory IO. + +------------------------------------- +See more information in Apache Ignite documentation: +https://apacheignite.readme.io/docs/durable-memory-tuning#section-enabling-direct-i-o + +and description of internal desing can be found in Wiki: +https://cwiki.apache.org/confluence/display/IGNITE/Ignite+Persistent+Store+-+under+the+hood#IgnitePersistentStore-underthehood-DirectI/O
