Greetings, I am testing how HDFS scales with very large number of blocks. I did the following setup:
Set the default blocks size to 1KB Started 8 insert processes, each inserting a 16MB file Repeated the insert 3 times, keeping the already inserted files in HDFS Repeated the entire experiment on one cluster with 4 and another with 11 identical datanodes (allocated through HOD) Results: The first 128MB (2^18 blocks) insert finished in 5 minutes. The second in 12 minutes. The third didn't finish within 1 hour. The 11-node cluster was marginally faster. Throughout this I was storing all available metrics. There were no signs of insufficient memory on any of the nodes; CPU usage and garbage collections were constant throughout. If anyone is interested I can provide the recorded metrics. I've attached a chart that looks clearly logarithmic. Can anyone please point to what could be the bottleneck here? I'm evaluating HDFS for usage scenarios requiring 2^(a lot more than 18) blocks. Bes <<insertion_rate_4_and_11_datanodes.JPG>> t Regards, Zlatin Balevsky _______________________________________________ This e-mail may contain information that is confidential, privileged or otherwise protected from disclosure. If you are not an intended recipient of this e-mail, do not duplicate or redistribute it by any means. Please delete it and any attachments and notify the sender that you have received it in error. Unless specifically indicated, this e-mail is not an offer to buy or sell or a solicitation to buy or sell any securities, investment products or other financial product or service, an official confirmation of any transaction, or an official statement of Barclays. Any views or opinions presented are solely those of the author and do not necessarily represent those of Barclays. This e-mail is subject to terms available at the following link: www.barcap.com/emaildisclaimer. By messaging with Barclays you consent to the foregoing. Barclays Capital is the investment banking division of Barclays Bank PLC, a company registered in England (number 1026167) with its registered office at 1 Churchill Place, London, E14 5HP. This email may relate to or be sent from other members of the Barclays Group. _______________________________________________
<<attachment: insertion_rate_4_and_11_datanodes.JPG>>