Hi there,

I am using my linode as an OwnCloud server for about 4 non-heavy users.

Otherwise I have Piwik installed to monitor usage and that's about it.

Yet I get about 2-3 emails a week about high disk io rate. Usually the rate is around 2400.

Here are the top 10 entries when I run "iotop":

 TID  PRIO  USER     DISK READ  DISK WRITE  SWAPIN     IO>    COMMAND                                                                                                              
 3072 be/4 mysql       0.00 B/s    0.00 B/s  0.00 %  0.00 % mysqld
    1 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % init
    2 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kthreadd]
    3 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [ksoftirqd/0]
    5 be/0 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/0:0H]
    6 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [kworker/u4:0]
 3073 be/4 mysql       0.00 B/s    0.00 B/s  0.00 %  0.00 % mysqld
    8 be/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [rcu_bh]
    9 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/0]
   10 rt/4 root        0.00 B/s    0.00 B/s  0.00 %  0.00 % [migration/1]

If I try to look at mysqld using "sudo lsof | grep mysqld" I get: http://pastebin.ubuntu.com/10487377/

Is this generally considered to be a high disk io rate? Is it something to worry about or can I ignore it and simply raise the threshold in my Linode Manager?

Maybe you have a job that runs occasionally and does a lot of disk access (e.g., log analysis)? If you've looked into it and satisfied yourself that the application performance is satisfactory, go ahead and raise the notification threshold - the default is just that, a default, and won't be appropriate for every use case.