1 Topic by sgjava

  • sgjava
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Topic: Periodic disk writes

NanoPi M1 1G quad core ARM
0.9.6 OPENLDAP edition
Ubuntu 16.04.2 LTS (3.4.113-sun8i #10 SMP PREEMPT Thu Feb 23 19:55:00 CET 2017 armv7l armv7l armv7l GNU/Linux)
nginx version: nginx/1.10.0 (Ubuntu)

I'm using Zabbix to monitor my iRedMail install and I'm seeing periodic iowait (disk access) about every 15 minutes or so and I'm not really using the server at this point. Is there some process that runs ~15 minutes? I attached the Zabbix CPU graph.

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Spider Email Archiver: On-Premises, lightweight email archiving software developed by iRedMail team. Supports Amazon S3 compatible storage and custom branding.

2 Reply by martinveasey

  • martinveasey
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Re: Periodic disk writes

This is a bit puzzling as it's not strictly every 15 minutes ->  from your chart *:45 seems regularly to be missed out, whereas there are spikes at roughly *:00, *:15 and *:30. Also, the spacing is a little irregular - the gaps are not quite even.

All the regular iRedMail process management I've seen seems to draw on the cron entries for the various sub-systems. I've not seen anything that operates three times per hour and I can't recall seeing anything on a 15 minute basis.

Have you tried working through the various crons as root?:

/etc/cron.d
/var/spool/cron/crontabs

Is it possible for you to get a more precise time from Zabbix and recursively grep your logs for anything interesting?

3 Reply by ZhangHuangbin

  • ZhangHuangbin
  • ZhangHuangbin
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Re: Periodic disk writes

Check root user's cron jobs, in old iRedMail release, we run an iRedAPD script (spf_to_greylist_whitelists.py) every 15 minutes (it was increased to ever 30 minutes in recent iRedMail releases).