Constant disk activity

[John Gorst]

I am running FreeNAS-9.3--STABLE-201505100553 on a HP Microserver with 8gb ram off a USB stick with 2x3TB disks in a mirror mainly as backup destination but has a few jails with Plex, Crashplan, Transmissiona nnd z-push (imap-->activesysnc)

I have noticed constant disk activity even when nothing is connected to the box, freshly rebooted and all jails switched off.

If I switch off syslog then the disk activity all but stops.

Issues
1) 300kb/sec seems to be a fair amount of constant data write, probably ok in the context of drive wear but still probably not ideal in terms of CPU/disk performance on this underpowered box

2) If syslog is logging 300kb/sec to my system, is that indicative of some major problem - that is an awful lot of log data!!

I have checked all the logs in /var/logs but can't see anything wildly unusual.

I note that syslog-ng also logs to
/var/db/system/syslog-adb946163d914f088dc14617dbc0bec3/log/debug.log

Is this usual?

I also note that there are CPU spikes every minute from autosnap.py, alert.py and autorepl.py
Is there a way to reduce the frequency of how often these are run?

Thanks for any help.

 

[SweetAndLow]

Someone should try searching! There are 100s of posts with this exact wording and question.

https://www.google.com/search?q=site:freenas.org constant disk activity&oq=site:freenas.org constant disk activity&aqs=chrome..69i57j69i58.19633j0j4&client=ms-android-verizon&sourceid=chrome-mobile&espv=1&ie=UTF-8

 

[John Gorst]

I agree there are a lot of similar topics but not the same. I went through a great number before posting.

For example the first two posts in your search indicate the writes are <100k/sec.... why is my log consuming ~300k/sec?

Also a lot of the other posts are talking about a similar issue which does NOT disappear when syslog is turned off.

 

[DrKK]

John:

You should take those "300 kb/s" figures with a grain of salt. They are not really integrated write speeds, but rather, more like instantaneous/peak write speeds. Most of that activity is written to the various syslog things, including that debug file, and the databases that make the "reporting" graphs. (Which is why the activity stops when you turn off the syslog). There should be no discernible effect on CPU, or power consumed. Your only "downside" which isn't even a downside, is that you won't be able to spin-down the drives for inactivity----but modern NAS drives aren't SUPPOSED to be spun down for inactivity---in some sense that's not even good for them.

The correct procedure here is not to worry about it.