[
https://issues.apache.org/jira/browse/HBASE-6572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14293910#comment-14293910
]
Ted Yu commented on HBASE-6572:
-------------------------------
Thinking about how store flushing can make use of hdfs storage policy, one
option is to allow setting storage policy for the directory path of the
specified column family.
Planning to create a sub-task for the above.
> Tiered HFile storage
> --------------------
>
> Key: HBASE-6572
> URL: https://issues.apache.org/jira/browse/HBASE-6572
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Andrew Purtell
>
> Consider how we might enable tiered HFile storage. If HDFS has the
> capability, we could create certain files on solid state devices where they
> might be frequently accessed, especially for random reads; and others (and by
> default) on spinning media as before. We could support the move of frequently
> read HFiles from spinning media to solid state. We already have CF statistics
> for this, would only need to add requisite admin interface; could even
> consider an autotiering option.
> Dhruba Borthakur did some early work in this area and wrote up his findings:
> http://hadoopblog.blogspot.com/2012/05/hadoop-and-solid-state-drives.html .
> It is important to note the findings but I suggest most of the
> recommendations are out of scope of this JIRA. This JIRA seeks to find an
> initial use case that produces a reasonable benefit, and serves as a testbed
> for further improvements. If I may paraphrase Dhruba's findings (any
> misstatements and errors are mine): First, the DFSClient code paths introduce
> significant latency, so the HDFS client (and presumably the DataNode, as the
> next bottleneck) will need significant work to knock that down. Need to
> investigate optimized (perhaps read-only) DFS clients, server side read and
> caching strategies. Second, RegionServers are heavily threaded and this
> imposes a lot of monitor contention and context switching cost. Need to
> investigate reducing the number of threads in a RegionServer, nonblocking IO
> and RPC.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
