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Weiwei Yang commented on HDFS-12443: ------------------------------------ Hi [~linyiqun] Please take a look at the pdf I just uploaded ^HDFS-12443-SCM-blockdeletion-throttle.pdf, the key issue here is we want to properly throttle the size of message sent to DN, see chart page 1 {{CommandQueue}}. In every interval, we want each DN gets a throttled number of {{DeletedBlocksCommand}} to process. But delLog has no notion of DN, so it's a bit difficult to get there. Please let me know your thought, thanks. > Ozone: Improve SCM block deletion throttling algorithm > ------------------------------------------------------- > > Key: HDFS-12443 > URL: https://issues.apache.org/jira/browse/HDFS-12443 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: ozone, scm > Reporter: Weiwei Yang > Assignee: Yiqun Lin > Labels: OzonePostMerge > Attachments: HDFS-12443-HDFS-7240.001.patch, > HDFS-12443-HDFS-7240.002.patch, HDFS-12443-HDFS-7240.002.patch, > HDFS-12443-SCM-blockdeletion-throttle.pdf > > > Currently SCM scans delLog to send deletion transactions to datanode > periodically, the throttling algorithm is simple, it scans at most > {{BLOCK_DELETE_TX_PER_REQUEST_LIMIT}} (by default 50) at a time. This is > non-optimal, worst case it might cache 50 TXs for 50 different DNs so each DN > will only get 1 TX to proceed in an interval, this will make the deletion > slow. An improvement to this is to make this throttling by datanode, e.g 50 > TXs per datanode per interval. -- This message was sent by Atlassian JIRA (v6.4.14#64029) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org