Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

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

I have attempted to use a tmpfs to speed up some heavily accessed files. I wanted to test the read and write speeds of both the HDD its self and a tmpfs. My results where strangely low for what I was expecting: dd if=/dev/zero of=/home/******/tmpfs/ bs=1k count=128k 131072+0 records in 131072+0 records out 134217728 bytes (134 MB) copied, 4.03752 seconds, 33.2 MB/s

The directory /home/******/tmpfs is a 200MB tmpfs that I mounted a little bit before.

I do not have much experience with tmpfs's and was wondering... Isn't this very slow? What can be done to speed this up? What is causing the slow speeds?

share|improve this question

That speed is suspiciously close to the speed of a somewhat slow hard drive. You may have run out of real memory and started swapping. How much free memory do you have?

share|improve this answer
free -m outputs: 1884 used (2043 total) 946 cache (1097 buffers) – Zac Fryle Sep 4 '11 at 2:34
The contents of tmpfs will contribute to that value in cache. What is the output of "swapon -s" – Aaron Jan 1 '15 at 2:08

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.