There are two indices (guava HashBiMaps) that map your ID into and out of Mahout IDs (HashBiMap<int, string>). There is one copy of each (row/user IDs and column/itemIDS) per physical machine that all local tasks consult. They are Spark broadcast values. These will grow linearly as the number of items and users grow and as the size of your IDs, treated as strings, grow. The hashmaps have some overhead but in large collections the main cost is the size of the application IDs stored as strings, Mahout’s IDs are ints.
On Jan 22, 2015, at 8:04 AM, Pasmanik, Paul <paul.pasma...@danteinc.com> wrote: I was able to get spark and mahout installed on EMR cluster as bootstrap actions and was able to run spark-itemsimilarity job via an EMR step with some modifications to mahout script (defining SPARK_HOME and making sure CLASSPATH is not picked up from the invoking script which is amazon's script-runner). I was only able to run this job using yarn-client (yarn-master is not able to submit to resource manager). In yarn-client mode the driver program runs in the client process and submits jobs to executors via yarn manager, so my question is how much memory does this driver need? Will the memory requirement vary based on the size of the input to spark-itemsimilarity? Thanks. -----Original Message----- From: Pasmanik, Paul [mailto:paul.pasma...@danteinc.com] Sent: Thursday, January 15, 2015 12:46 PM To: user@mahout.apache.org Subject: mahout 1.0 on EMR with spark Has anyone tried running mahout 1.0 on EMR with Spark? I've used instructions at https://github.com/awslabs/emr-bootstrap-actions/tree/master/spark to get EMR cluster running spark. I am now able to deploy EMR cluster with Spark using AWS JAVA APIs. EMR allows running a custom script as bootstrap action which I can use to install mahout. What I am trying to figure out is whether I would need to build mahout every time I start EMR cluster or have pre-built artifacts and develop a script similar to what awslab is using to install spark? Thanks. ________________________________ The information contained in this electronic transmission is intended only for the use of the recipient and may be confidential and privileged. Unauthorized use, disclosure, or reproduction is strictly prohibited and may be unlawful. If you have received this electronic transmission in error, please notify the sender immediately.
