After updating to 25.10.0, I noticed that my disks wake up every 90 minutes. This was not the case in the previous version 25.04.2.1. To illustrate the behavior, I have attached a screenshot of the power consumption.
I used these settings:
HDD Standby: 30
Advanced Power Management: Level 1
In order to narrow down the problem source, I have stopped all apps and disabled all shares. I don’t run any VM’s. So I suspect there is some activity of TrueNAS itself that accesses the discs, but I have no idea where to look or what to do, and so I would appreciate any help.
EDIT: I should mention that the boot pool is on different drives.
I think this is more than just a bug. I think it is a question of what TrueNAS is supposed to be used for. It seems that TrueNAS is always optimized for performance.
I run two TrueNAS servers: One main server and a backup server with a replica of the main server. Both have spinning drives for capacity and SSD’s.
Needless to say that the backup server sees very little activity. The only thing that happens on the server is that it periodically gathers backups from other computers and runs a TrueNAS replication task. To ensure that drives will sleep, I have disabled SMART data collection.
Ideally, it would almost always sleep and thus use minimal power. It would only wake when the admin connects to the GUI and when there was a task to run. That has not been possible to configure easily. Until now has consumed about 150 USD/EUR of power each year. With the change to SMART data collection in 25.10, it will jump to about 400 USD/EUR (based on my measurements).
I really like TrueNAS, but right now I am considering dropping TrueNAS on the backup box and just run bare Linux with OpenZFS. That way I would have far more control over power usage. Obviously, that would come with added complexity. Ideally, TrueNAS would have a general setting where one could choose its role. Application server, file server, backup server, etc.
That way decisions affecting power usage could be made with that in mind though it would require more testing.
Just FYI, I have no reverted back to version 25.04.2.1, and everything is back to normal. I do hope this will be fixed soon (the bug has been reported October 4, 2025).
FWIW: I have done this and it was not difficult at all if you know your way around Linux & ZFS.
Use Case:
Wanted a universally recoverable solution eliminating TrueNAS from my offsite recovery and be able to recover anywhere on anything I could get my hands on that runs Linux. TrueNAS is not always friendly here.
Ability to export and import a rotating set of 4 physical hard drives to offsite storage on a quarterly basis.
TrueNAS remains primary and backup replica targets for clients and mounts.
How:
Using Ubuntu 24.04 LTS, Webmin and Poolsman ZFS management interface. CLI is cool but much easier in a GUI to deal with ZFS…
Built an Ubuntu server, configured OpenZFS, established SSL logins & credentials, replicated a seed set of snapshots via mbuffer and zfs send/receive streams.
Daily a TrueNAS cron job executes zfsbud which handles the replication tasks of existing TrueNAS snapshots. TrueNAS jobs are ok but I didn’t want to have a dependency on TrueNAS schedulling, UID GID or be bound to my TrueNAS snapshot pool. Instead, I selectively grab weekly and monthly snapshots for the quarter and push them across to the offsite box.
