Thanks Pradeep. Does it mean this job is a bad candidate for MR? Interestingly, running the cmdline '/bin/grep' under a streaming job provides (1) Much better disk throughput and, (2) CPU load is almost evenly spread across all cores/threads (no CPU gets pegged to 100%).
On Thu, Oct 10, 2013 at 11:15 AM, Pradeep Gollakota <pradeep...@gmail.com>wrote: > Actually... I believe that is expected behavior. Since your CPU is pegged > at 100% you're not going to be IO bound. Typically jobs tend to be CPU > bound or IO bound. If you're CPU bound you expect to see low IO throughput. > If you're IO bound, you expect to see low CPU usage. > > > On Thu, Oct 10, 2013 at 11:05 AM, Xuri Nagarin <secs...@gmail.com> wrote: > >> Hi, >> >> I have a simple Grep job (from bundled examples) that I am running on a >> 11-node cluster. Each node is 2x8-core Intel Xeons (shows 32 CPUs with HT >> on), 64GB RAM and 8 x 1TB disks. I have mappers set to 20 per node. >> >> When I run the Grep job, I notice that CPU gets pegged to 100% on >> multiple cores but disk throughput remains a dismal 1-2 Mbytes/sec on a >> single disk on each node. So I guess, the cluster is poorly performing in >> terms of disk IO. Running Terasort, I see each disk puts out 25-35 >> Mbytes/sec with a total cluster throughput of above 1.5 Gbytes/sec. >> >> How do I go about re-configuring or re-writing the job to utilize maximum >> disk IO? >> >> TIA, >> >> Xuri >> >> >> >
