Nagging concerns and questions

[BigMike]

I run FreeNAS at home - my system is perfectly stable and performs well. I am not a sysadmin expert but I do read the forums and have accumulated some nagging questions/concerns I wish an expert here could answer for me. Here is the question set in no particular order:

- how would I know if ECC memory is finding, or has found or corrected a problem? Does FreeNAS monitor this, or is that something I should be watching for somehow? If so how?
- I originally installed FreeNAS 9.x, upgraded to Corral, and then fell back to 9.x, then upgraded to 11.0 ... I wonder if installing plugins, Docker installs, and now jails and plugins again has left any residual file structures on my system. If I am willing to delete my current plugins and jails before moving to 11.1 soon, where would I look to see if there are plugin or jail (or Docker remnants from my Corral adventure) in my file system that could be deleted?
- I boot from a mirrored pair of 16GB USB2 memory sticks. Am I correct that FreeNAS 11.x now writes data to the boot drives (log files)? Is this about as dumb as ASRock watchdog memory writes killing their own motherboards (well, the USB sticks are easy to replace anyhow...)? Could/should these logs be moved to a data volume, or does that violate a desire to keep system and users data separate?
- where is system swap file stored? If the drive where swap is stored fails, what happens to the system and my data?
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Note: My FreeNAS system is very close to being a clone of a FreeNAS mini - the ASRock C2758 miniITX, 16G ECC memory, 4 x 4TB WD Red drives. Running 11.0U4, plex server plugin and logitech mediaserver in a jail.

 

[wblock]

Multiple questions in a single thread usually do not get the best of answers, but I'll try. For future questions, post one per thread, with a very specific thread name to attract the people who know about that subject.

* ECC memory errors should appear in /var/log/messages, although I don't have any examples to show.
* To find obsolete files and directories would kind of require knowing what could have been created. AFAIK there is no easy way to do that.
* Every version of FreeNAS you have used has run from the boot devices. The running from RAM thing went away several years ago. The system dataset can be moved to a different location. I can't recall whether there is direct control of syslog stuff, but that could be used to direct logging elsewhere also.
* When a volume is created, 2GB of each disk is used as a swap partition.

 

[BigMike]

Thanks for trying! Here is what I think I know now...
- ECC memories should appear in var/log/messages. ECC errors might also be logged by the server motherboards management system (as the system admin I should be checking for these errors) but FreeNAS doesn't check or warn.
- Since I have created jails (and Dockers while running Corral) and then rolled back, I probably do have jail and Docker remnants on my system. I still don't know where Coral would have put Docker and jail stuff, or how to find it and safely delete it ...
- Boot devices (USB flash memory) should not fail from overuse, since the system dataset can be moved off the boot device (and I think it is by default in newer FreeNAS releases?)
- swap file is spread across all disks - I don't know if it is protected by ZFS, or whether the loss of any single drive while swap file is in use could bring the system down?

 

[gpsguy]

In theory, it's possible.

FreeNAS 11.1 (now in beta), includes support for mirrored swap partitions. See - https://bugs.freenas.org/issues/23523

swap file is spread across all disks - I don't know if it is protected by ZFS, or whether the loss of any single drive while swap file is in use could bring the system down?