Daniel's Blog

Testing Disk IO Speeds vs Network Speeds

Testing the disk IO

First, the disk was mounted under /mnt/spare

To test the disk space I ran:

$ sudo dd if=/dev/zero of=here bs=1G count=1 oflag=direct
1+0 records in
1+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 4.74977 s, 226 MB/s

226 MB/s is fine as it is a SATA Hard Disk Drive.

Then I tested over the network. I created an iperf server on port 12311

$ sudo iperf -s -p 12311 
------------------------------------------------------------
Server listening on TCP port 12311
TCP window size:  128 KByte (default)
------------------------------------------------------------
[  4] local 10.1.1.241 port 12311 connected with 10.1.1.245 port 33506
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   989 MBytes   828 Mbits/sec

828 Mbits/sec ~= 103.5 MB/s

So the testing revealed that the network is slower than the disk... :/ This was unexpected as the network is 10GBe which should be about 1250 MB/s. I hypothesis that the network is actually 1GBe and I was told incorrectly.