Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

When I run gunzip on a 1.7GB file (which generates an 8GB file) on an EBS volume, pdflush freezes after gunzip runs and the CPU hangs indefinitely at 100% IO Wait. Here's the output from 'ps aux | grep pdflush'. Note the D status

root 87 0.0 0.0 0 0 ? D 06:18 0:00 pdflush root 88 0.0 0.0 0 0 ? D 06:18 0:00 pdflush

The only solution is to kill the pdflush processes. The processes don't die immediately either.

This problem is repeatable and happens with new instances. I'm running 2xlarge instances and I have way more RAM free than is being used (i.e. /proc/meminfo shows 20+GB MemFree)

Has anyone found a workaround to this problem in the past?

Thanks for any thoughts.


share|improve this question

Are you using a single ebs volume ? You can try using a striped set of 4. This will give you better io performance.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.