We're using cloud hosting for some of our backend servers and we noticed that performance on the disks (which as confirmed by the provider are shared with other customers) vary depending on the time/day of the week. We would like to find out how performance evolves throughout the day/week to decide whether it's worth moving to another provider (that we would benchmark too).
Here is what we've been doing so far:
-use munin
for the graphing.
-create a munin plugin with hdparm -t /dev/sda1
to test read speed.
-create a munin plugin with dd if=/dev/sda1 of=/tmp/test bs=512k count=512 oflag=direct
to test write speed.
Both hdparm
and dd
run for less than 10 seconds, which means that the server is kept busy for 0.6%
of the time which we find acceptable (10+10 seconds / 300 seconds (that's how frequently munin runs) * 100).
The problem is that we're getting around 250MB/s
for read
speed and 200MB/s
for write
whereas I would expect the former to be much higher than the latter (FYI we're using 15K rpm SAS
drives).
Q: Are there other ways of measuring read/write speed ? (we need things that can be executed in 10 seconds or less)