Very Slow tmpfs Read/Write speeds

Question

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/test.data 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?

score 1 · Answer 1 · answered Sep 04 '11 at 02:22

1

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?

answered Sep 04 '11 at 02:22

Snowhare

167
2

`free -m` outputs: 1884 used (2043 total) 946 cache (1097 buffers) – Zac Fryle Sep 04 '11 at 02:34
The contents of tmpfs will contribute to that value in cache. What is the output of "swapon -s" – Aaron Jan 01 '15 at 02:08

Very Slow tmpfs Read/Write speeds

1 Answers1