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yucai commented on SPARK-12196: ------------------------------- Sorry, I have to delete this PR because of my wrong github operation, I will send a new one ASAP. > Store blocks in storage devices with hierarchy way > -------------------------------------------------- > > Key: SPARK-12196 > URL: https://issues.apache.org/jira/browse/SPARK-12196 > Project: Spark > Issue Type: New Feature > Components: Spark Core > Reporter: yucai > > *Problem* > Nowadays, users have both SSDs and HDDs. > SSDs have great performance, but capacity is small. HDDs have good capacity, > but x2-x3 lower than SSDs. > How can we get both good? > *Solution* > Our idea is to build hierarchy store: use SSDs as cache and HDDs as backup > storage. > When Spark core allocates blocks for RDD (either shuffle or RDD cache), it > gets blocks from SSDs first, and when SSD’s useable space is less than some > threshold, getting blocks from HDDs. > In our implementation, we actually go further. We support a way to build any > level hierarchy store access all storage medias (NVM, SSD, HDD etc.). > *Performance* > 1. At the best case, our solution performs the same as all SSDs. > 2. At the worst case, like all data are spilled to HDDs, no performance > regression. > 3. Compared with all HDDs, hierarchy store improves more than *_x1.86_* (it > could be higher, CPU reaches bottleneck in our test environment). > 4. Compared with Tachyon, our hierarchy store still *_x1.3_* faster. Because > we support both RDD cache and shuffle and no extra inter process > communication. > *Usage* > 1. In spark-default.xml, configure spark.hierarchyStore. > {code} > spark.hierarchyStore nvm 50GB, ssd 80GB > {code} > It builds a 3 layers hierarchy store: the 1st is "nvm", the 2nd is "sdd", all > the rest form the last layer. > 2. Configuration the "nvm", "ssd" location in local dir, like spark.local.dir > or yarn.nodemanager.local-dirs. > {code} > spark.local.dir=/mnt/nvm1,/mnt/ssd1,/mnt/ssd2,/mnt/ssd3,/mnt/disk1,/mnt/disk2,/mnt/disk3,/mnt/disk4,/mnt/others > {code} > After then, restart your Spark application, it will allocate blocks from nvm > first. > When nvm's usable space is less than 50GB, it starts to allocate from ssd. > When ssd's usable space is less than 80GB, it starts to allocate from the > last layer. -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org