Description of problem:

  Virtualized RGW host goes into loop causing 100% CPU utilization.

Version-Release number of selected component (if applicable):

  ceph-radosgw-0.94.5-12.el7cp.x86_64
  RHEL 7.2 servers running OpenStack Kilo with Ceph Storage Backend
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Customer reports that after setting up 3 virtualized RGW nodes several months ago & during testing they've noticed that all 3 are running at 100% CPU (95% of the time) even though they don'think they are being heavily used. We requested RGW debug logs &  they are attached to case 01705883 as 'client.radosgw.log.gz'  

The customer also provided the following details when asked for a specific timeframe to focus on:

"Between 10:10 & 10:20 AM . And it was not using ALL CPU's, but it was using more than 50% (which should have been the limit) and if we had left it alone it would have eventually used all the CPU's. Below is the partial output from sar for that timeframe ...

09:50:01 AM     all      0.07      0.00      0.04      0.00      0.00     99.89
10:00:01 AM     all      0.08      0.00      0.06      0.00      0.00     99.86
10:10:01 AM     all      0.31      0.00      0.22      0.00      0.00     99.48
10:20:01 AM     all     29.40      0.00     30.32      0.05      0.04     40.20
10:30:01 AM     all      9.51      0.00     13.63      0.01      0.01     76.84"

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Log analysis of 'log entries per second' ramps up quickly starting at the 10:09:41 mark in the debug log, and appears to go into a loop around that time.