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https://issues.apache.org/jira/browse/HDFS-14745?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Rakesh Radhakrishnan updated HDFS-14745:
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Fix Version/s: (was: 3.3.0)
3.1.4
Release Note: Non-volatile storage class memory (SCM, also known as
persistent memory) is supported in HDFS cache. To enable SCM cache, user just
needs to configure SCM volume for property “dfs.datanode.cache.pmem.dirs” in
hdfs-site.xml. And all HDFS cache directives keep unchanged. There are two
implementations for HDFS SCM Cache, one is pure java code implementation and
the other is native PMDK based implementation. The latter implementation can
bring user better performance gain in cache write and cache read. If PMDK
native libs could be loaded, it will use PMDK based implementation otherwise it
will fallback to java code implementation. To enable PMDK based implementation,
user should install PMDK library by referring to the official site
http://pmem.io/. Then, build Hadoop with PMDK support by referring to "PMDK
library build options" section in `BUILDING.txt` in the source code. If
multiple SCM volumes are configured, a round-robin policy is used to select an
available volume for caching a block. Consistent with DRAM cache, SCM cache
also has no cache eviction mechanism. When DataNode receives a data read
request from a client, if the corresponding block is cached into SCM, DataNode
will instantiate an InputStream with the block location path on SCM (pure java
implementation) or cache address on SCM (PMDK based implementation). Once the
InputStream is created, DataNode will send the cached data to the client.
Please refer "Centralized Cache Management" guide for more details.
Resolution: Fixed
Status: Resolved (was: Patch Available)
> Backport HDFS persistent memory read cache support to branch-3.1
> ----------------------------------------------------------------
>
> Key: HDFS-14745
> URL: https://issues.apache.org/jira/browse/HDFS-14745
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Feilong He
> Assignee: Feilong He
> Priority: Major
> Labels: cache, datanode
> Fix For: 3.1.4
>
> Attachments: HDFS-14745-branch-3.1-000.patch,
> HDFS-14745-branch-3.1-001.patch, HDFS-14745-branch-3.1-002.patch,
> HDFS-14745-branch-3.1-003.patch
>
>
> We are proposing to backport the patches for HDFS-13762, HDFS persistent
> memory read cache support, to branch-3.1.
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