Unusual rise in disk reads without any significant activity

Question

I have a Ubuntu VM instance on Azure. Without any anomaly in the code or activities carried out server freezes and when I try to run any command it pops up a -bash: fork: Cannot allocate memory.

I have a python server running along with a mongodb and mysql. I don't see any reason for such disk access. Also there is no significant or CPU or network IO load.

Screenshot of a disk IO on azure dashboard

Has anyone experienced such behavior? I haven't seen such behavior on my test environment or for nearly 14days in production until today.

Use `top` to see what eat free RAM memory. – Mikhail Khirgiy Jun 01 '17 at 16:13 — Mikhail Khirgiy, Jun 01 '17 at 16:13
There is not enough information in your question. – Alexander Tolkachev Jun 02 '17 at 07:12 — Alexander Tolkachev, Jun 02 '17 at 07:12

score 0 · Answer 1 · answered Jun 02 '17 at 07:27

There is complicated question.

Error Cannot allocate memory showed when you don't have enough Virtual Memory to allocate memory for process start, fork or run new thread. For disk IO, it could be some monthly activity in cron, you could check for activities in file /etc/crontab and in folders /etc/cron.d and /etc/cron.monthly.

To know whats with your system, you could install atop and start it as service, it will save system statistics and you could check system state after issue.

Unusual rise in disk reads without any significant activity

1 Answers1