Hello I use servers Ubuntu 14.04 LTS with KVM+libvirt. Last time I had strange situation.
First I had node Ubuntu 14.04.2 LTS with kernel 3.13.0-46-generic, and VM Ubuntu 14.04.2 LTS with kernel 3.13.0-46-generic + postgresql-9.3 9.3.6-0ubuntu0.14.04.
Next I upgraded node and VM to Ubuntu 14.04.4 LTS with kernel 3.19.0-58-generic, and postgresql-9.3_9.3.4-1.
And I saw my Database Server became too slow. I had high load average on the same load profile.
Then I rolled back only my VM to Ubuntu 14.04.2 and my DB server started working normally.
I didn't have time for deep research, may be this post will be helpful.
First I had node Ubuntu 14.04.2 LTS with kernel 3.13.0-46-generic, and VM Ubuntu 14.04.2 LTS with kernel 3.13.0-46-generic + postgresql-9.3 9.3.6-0ubuntu0.14.04.
Next I upgraded node and VM to Ubuntu 14.04.4 LTS with kernel 3.19.0-58-generic, and postgresql-9.3_9.3.4-1.
And I saw my Database Server became too slow. I had high load average on the same load profile.
Then I rolled back only my VM to Ubuntu 14.04.2 and my DB server started working normally.
I didn't have time for deep research, may be this post will be helpful.