HDD Sleeping not working if there is a jail running.

[joeschmuck]

So I was looking into this problem for someone else and what it looks like I found is if you have a jail running the hard drives will not sleep. This seems a bit hard to swallow since I haven't heard of any complaints and the hard drives not spinning down usually gets a lot of attention.

First this is for FreNAS 9.1.1 Release on my real NAS (specs in my tagline).

Through a lot of investigative work it looks like this is true and I'd like someone else to confirm this as it could be only on my machine.

What I've done was installed the MiniDLNA plugin which creates a single jail. I monitored the hard drive status using smartctl and set my idle for 5 minutes in the GUI and also for good measure I used the ataidle command a few times just to ensure the GUI did work (the GUI does work). I setup a script to automate the monitoring as well.

With the MiniDLNA installed the drives would not go into Standby. I removed the MiniDLNA plugin which also removed the jail and reran my tests and the hard drives go into Standby.

Next I installed only a jail. I didn't do any configuration of the jail, it was only running. The drives did not go into Standby. I stopped the jail and the drives go into Standby.

Now this may be just a side affect that we will have to accept when running a jail but this is new behavior from FreeNAS 8.x.

I did not reinstall FreeNAS 9.1.1 on my system so I cannot rule out some setting I have and I will not be reloading FreeNAS because I just brought my server back to the basement and it's staying there unless I have a problem that warrants it.

 

[cyberjock]

Yeah, this was discussed somewhere else a while back (pre 9.x?) and the answer was that the logs are on the pool, so naturally any disks on that pool will not sleep. The recommended solution was to use a different pool for your jail if you really need sleep. Even a small 60GB SSD would be rockin' for that task as the jails don't exactly consume massive amounts of disk space.

 

[joeschmuck]

Thanks for the info. I now know why I didn't see this problem in 8.3.x, at the time I was using a USB Flash drive (UFS format) for my jails. Well I guess the solution is like you said, place it on another pool. I guess there could be another option, assuming it's only the logs, well the logs could be moved to /var and that would help out but you lose any log data upon reboot which isn't idea at all.

So I guess this is where a good USB3.0 flash drive would come in very handy.

Of course this problem doesn't impact me since I leave my drives spinning all the time but others will want to sleep those drives.