[
https://issues.apache.org/jira/browse/HADOOP-14766?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16124648#comment-16124648
]
Steve Loughran commented on HADOOP-14766:
-----------------------------------------
+if you are trying to reduce risk of throttling, you may even want to look at
filesize before choosing which to upload, & try to mix big files with little
ones. You'd want to sort them & start the largest few off first to stop it
being a bottleneck, then go for the rest.
without store throttling and bandwidth limitations, the optimal scheduling
would seem to be just queue the largest files for upload first & let them sort
themselves out, finishing off with all the small files after. But: those small
files take up lots of HTTP requests (3x HEAD & 1 PUT & 1 DELETE with
depth(file) entries), & with SSE-KMS, one createKey call. Mixing them in with
the larger uploads, as well as mixing paths, would appear to be less prone to
throttling
> Add an object store high performance dfs put command
> ----------------------------------------------------
>
> Key: HADOOP-14766
> URL: https://issues.apache.org/jira/browse/HADOOP-14766
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs, fs/s3
> Affects Versions: 2.8.1
> Reporter: Steve Loughran
>
> {{hdfs put local s3a://path}} is suboptimal as it treewalks down down the
> source tree then, sequentially, copies up the file through copying the file
> (opened as a stream) contents to a buffer, writes that to the dest file,
> repeats.
> For S3A that hurts because
> * it;s doing the upload inefficiently: the file can be uploaded just by
> handling the pathname to the AWS xter manager
> * it is doing it sequentially, when some parallelised upload would work.
> * as the ordering of the files to upload is a recursive treewalk, it doesn't
> spread the upload across multiple shards.
> Better:
> * build the list of files to upload
> * upload in parallel, picking entries from the list at random and spreading
> across a pool of uploaders
> * upload straight from local file (copyFromLocalFile()
> * track IO load (files created/second) to estimate risk of throttling.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
