/system share spread over cache + disk

[TechnIx]

Hello! I have spent the last month perfecting my Unraid NAS build and it's been awesome - I have understood & solved most of the challenges I've faced with my build.

 

I noticed one strange thing though that I couldn't figure out and it's bugging me.

 

The /system share, I currently have it set to Use Cache Disk-> Prefer

Looking at the share, it's clearly spread out over both the Cache and Disk1

 

Makes sense, I guess, since it's not cache only - but if I go into the terminal and look at what is stored on each, clearly the files are stored twice!

 

If I actually look at the files, they are definitely not the same files... each pair of files have different timestamps. The more recent docker.img & libvirt.img are on the cache, while the older ones (marked Jan 8 ) are both on the disk

 

Now my question is - what should I do? I don't run any VM's, but I do run about 5 dockers. I would like to set the /system share to be Cache Only, without damaging any of my dockers. I am not 100% sure what these files do *exactly* so I am not sure if it's safe to delete the older files marked as Jan 8, or how to tell if they are being used or not.

 

Thanks

[Squid]

4 hours ago, TechnIx said:

I am not 100% sure what these files do *exactly*

docker.img:  Stores all of the images for your docker applications

libvirt.img: As far as you're concerned, it stores the xml files for the VMs

 

Delete the oldest versions (disk 1)  Probably what happened here is that you originally set up your system without a cache drive, and those .img files wound up on disk #1.  Later on you added a cache drive and then told unRaid in its settings to explicitly put them onto the cache drive.

 

4 hours ago, TechnIx said:

I don't run any VM's, but I do run about 5 dockers.

Worst case scenario when deleting the docker.img if you get the wrong one is that you lose your apps.  Simply go to Apps, Previous apps and reinstall them from there.  No mods to the templates will be required.

[TechnIx]

That makes sense, I didn't have a cache drive to start with.

 

I deleted my disk1/system folder in the terminal, checked that all my dockers were still there and working, and then set the /system share to only use cache drive. All went smoothly, thanks! I was just extra worried because the folder was called system   - I didn't want to break anything important!

[JonathanM]

The mover script will only move files that aren't open, so to transition from no cache to adding one requires that you run the mover script while the VM and docker services are not running.

 

No harm no foul in your case, but be aware that cache prefer shares can get files "stuck" on the array if they are consistently in use while the mover runs.

[SSD]

I noticed this happened on a new build I am doing. It applied to system, appdata, domains, and one other I think. I deleted them from the array disk. But I think this is probably something @limetech would want to hear about if it is affecting others as well. I actually wound up losing a VM XML in the shuffle, but it was easily recreated as I had the image file. But other users might not know how to do that.

[JonathanM]

Thinking about it, there probably ought to be a notation in the FAQ about adding a cache drive to run the mover with services disabled for the initial run up. It's probably still going to be an ongoing issue though.

 

Maybe the mover script ought to have an option to log only files that DIDN'T get moved because they were open but would otherwise be targets for moving.

[Pete_Stonehiller]

It's an old post, but I thought it's at the right place.. what happens, if my cache drive (with docker.img and libvirt is on cache) decayed? I will change my Cache drive - for sure. But does unraid will start the array? What will be missing? Is it useful, to backup the 2 files? If I dont change anything at my VM Settins, the libvirt will be static - or not?

[JorgeB]

Docker image can easily be recreated, libvirt should be backed up if you have VMs, if you don't it's not needed.

[Pete_Stonehiller]

1 hour ago, JorgeB said:

Docker image can easily be recreated, libvirt should be backed up if you have VMs, if you don't it's not needed.

Thanks for your answer - how could I recreate the docker image? 

I got VMs - is this a "working" file (while using VMs) or is it static and I could backup it manually once? 

[ChatNoir]

44 minutes ago, Pete_Stonehiller said:

Thanks for your answer - how could I recreate the docker image?

Simply by reinstalling the dockers as they were before from the Previous Apps section of Community Application.

[JorgeB]

1 hour ago, Pete_Stonehiller said:

or is it static and I could backup it manually once? 

It's static unless you add or change any VM configuration.