Is constant small amounts of disk activity normal

[Craig321]

While I realise there will constantly be activity as I'm running 5 jails, CIFS, etc. I have noticed my disks reading or writing every few seconds which has started recently.

I have switched off all my jails and services, but it still has that small activity every few seconds.

There are no scrubs running and no SMART checks/tests scheduled to run at the moment

FreeNAS-9.2.1.6-RELEASE-x64 (ddd1e39), 8GB RAM in HP N54L, ZFS RAID Z1 pool with 4x 1.5TB, CIFS enabled.

I have attached a screenshot - you can see the constant small spikes which is when I can hear the drives reading/writing. The graph is the same for all 4 disks in the pool.

Any ideas?
Thanks.

 

[cyberjock]

Totally normal. This is stuff that's being put in .system dataset, which is almost certainly located in that pool.

 

[Whattteva]

I noticed a bunch of stuff in .system, one of which is syslog, which appears to contain all of the system logs.
It appears that /var/log is now a symbolic link to .system/syslog/log
Does this mean that logs are now persistent by default?

Also, since I do not see .system dataset anywhere in the web UI. I assume this is hidden and not shown on the web UI?

 

[no_connection]

.system dataset was visible at one point for me, but seems to be hidden now.
I believe both graphs and logs are persistent now.

 

[Whattteva]

I suppose it was a good decision for me to upgrade from 9.1.1 then.
I've always wondered why the logs weren't made persistent for so long by default, seeing as they could be very useful for troubleshooting.
I do wonder this though: What happens if you have no zpool, would it just default to the old non-persistent behavior?

 

[cyberjock]

The logs are non-persistent until you set a .system dataset. I believe on pool create it automatically chooses that pool for you as Samba4 needs a persistent storage location to do its magic.

 

[Craig321]

Totally normal. This is stuff that's being put in .system dataset, which is almost certainly located in that pool.

Thanks. I've come across loads of your posts round here, all extremely informative/helpful - big thanks from me for all the info & help you give on this forum :)

 

[Whattteva]

The logs are non-persistent until you set a .system dataset. I believe on pool create it automatically chooses that pool for you as Samba4 needs a persistent storage location to do its magic.

You sure about this? I have NEVER created that dataset but "zfs list" lists 5 datasets related to the .system dataset as soon as I upgraded from 9.1.1

 

[Craig321]

You sure about this? I have NEVER created that dataset but "zfs list" lists 5 datasets related to the .system dataset as soon as I upgraded from 9.1.1

The .system folder gets created automatically and put on the pool. You can change it through Settings > System Dataset.

 

[cyberjock]

Correct whattteva. I was referring to fresh installs. For upgrades as soon as you upgrade it'll create it on your first pool as this is necessary for Samba4 to function. It MUST happen pretty early on in the setup/upgrade process or Samba4 won't work.

 

[Whattteva]

Ah, now that makes sense. Thanks for clarifying that!

 

[SmallGuy]

Sorry to jump here, but what's about if you create the .system dataset on 9.2.0 or below (thinking since 9.1.1), and then upgrade to 9.2.1.x? Is it seamless?
To be clear, today I don't have any .system dataset, but ask myself if it is a mistake to create it under 9.2.0 to see how it works (only for the log point of view), and if it would be a problem for upgrading later (thinking of samba point of view)?

 

[Whattteva]

I'd imagine it'd only be seamless if the dataset you created is located under the same dataset listed under Settings -> System Dataset tab. Otherwise, it'd probably just assume there isn't one already available and create a new one under that dataset configured in Settings -> System Dataset.