What is IO rate? Should I be worried if I get a disk io rate notification?
Linode
Linode Staff
I received a warning email. (Your Linode has exceeded the notification threshold (10000) for disk io rate by averaging 15355.45 for the last 2 hours. )
Can you tell me what IO rate is? Should I raise this value? Or has my website been attacked?
1 Reply
rmoyer
Linode Staff
Anything that uses your Linode's disk (disk reads or disk writes) will generate IO. You will also generate IO if you run out of memory and start using your swap disk. In general, a spike in IO is not necessarily problematic, and does not necessarily mean that anything is wrong, but it would be a good idea to investigate its cause.
Here is what I would suggest:
- Check your memory usage to see if you ran out of memory and used the swap disk
free -m
Does this correspond with an increase in traffic to your site? If your site under heavier use, that could correspond with higher io.
Review your Linode's historical usage. Is this happening at regular intervals? Could you have a scheduled task that is running?
Investigate what process is using io. Tools such as iotop can be very helpful in this regard.
Finding the process that is leading to this usage is likely the best way to assuage your concerns of whether or not this is a result of a compromise, or something to be expected for your site.