[MAPREDUCE-3784] maxActiveApplications(|PerUser) per queue is too low for small clusters

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.23.0
• Fix Version/s: 0.23.1
• Component/s: mrv2
• Target Version/s: 0.23.1
• Hadoop Flags: Reviewed
• Release Note: Fixed CapacityScheduler so that maxActiveApplication and maxActiveApplicationsPerUser per queue are not too low for small clusters.
• Assignee: Arun Murthy
• Reporter: Ramya Sunil
• Created: 01/Feb/12 22:46
• Updated: 05/Mar/12 02:49
• Resolved: 03/Feb/12 01:18

Description

We ran into this issue while testing on small clusters.
On a 7node cluster with 8G per node, for a queue with absolute capacity 30%, user limit 100%, maxActiveApplications and maxActiveApplicationsPerUser is calculated to be 1.
This means that even though the queue has 17GB(0.3*8*7), only 1 user can run 1 app at a given time queuing up rest of the apps/users. This hurts performance on small clusters.