VM's and Docker on unassigned device?


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Hi!

 

I just recently built a "homeserver" of some old hardware (Gigabyte UD5, 4930K and 64GB RAM and some WD RED 4TB) and a couple of new disks.

From the looks of it Unraid is the server OS I'm looking for, so I decided to give it a shot.

 

Since it will be moving a lot of big files I didn't really want to use an SSD as a cache-drive, so I took one of my old "WD RED 4TB".

 

But I have noticed that the VM's and Dockers do take a hit when the big files are beeing written, so my question before I decide:

Is it possible to store the dockers and VM's on an SSD as an unassigned device, or is it any downside to this if possible?

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51 minutes ago, Koenig said:

I hope the same goes for the Dockers?

Yes

 

Another approach is to use SSD as cache but don't cache user share writes. This saves all the cache SSD for docker / VMs and writes to user shares are immediately protected by parity. If you still want a little more performance on writing to user shares on the array there is turbo-write mode. Not as fast as writing to cache but doesn't have the disadvantages of temporarily having your user share data on cache, where it will be unprotected (unless using a cache-pool) until moved (which just delays the performance hit of writing to the array).

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10 minutes ago, Koenig said:

OK, I see.

 

Maybe I'll switch it up later, but for now I'll go for my first thought.

 

And then another question popped up as I connected my SSD: What filesystem to use? Any recommendations here?

If you only want to read the drive on unRAID then I would go with XFS.    If you want to read it on another system then I would suggest formatting it on that system to a supported file system before plugging it into unRAID.

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20 minutes ago, itimpi said:

If you only want to read the drive on unRAID then I would go with XFS.    If you want to read it on another system then I would suggest formatting it on that system to a supported file system before plugging it into unRAID.

 

Only by Unraid.

 

Now I have to figure out how to move the already existing VM's and the dockers...

 

Anyone have a writeup about such things?

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So what I did was in a console:

 

cp -a /mnt/user/appdata/. /mnt/disks/SSD/appdata/

cp -a /mnt/user/system/. /mnt/disks/SSD/system/

cp -a /mnt/user/domains/. /mnt/disks/SSD/domains/

 

And then I changed the settings under VM-manager (libvirt and vdisks) to the new locations and the same for Docker (docker.img and appdata)

And lastly I changed the settings for each VM I had already created.

 

I hope this will do it.

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  • 1 year later...
9 minutes ago, tarzan said:

For anyone tempting to do this, don’t! I did it today and have various issues afterwards (dockers that can’t write to the file system, automatic recreation of user shares etc. )

 

I’m gonna try this approach instead> https://forums.serverbuilds.net/t/moving-your-docker-image-and-appdata-to-an-unassigned-drive/1478/7

You have done something wrong somewhere or there's a fundamental issue with your setup.

For example,"automatic recreation of user shares" suggest you have not reconfigured the dockers correctly.

 

Having VM's / dockers on UD is certainly advanced config and thus requires some technical skills to implement.

Nevertheless, your specific issue doesn't warrant a generic "don't" recommendation.

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  • 3 months later...

Just a question in relation to docker spacifically... i have offloaded my appdata and .img to a UD. I keep getting the error relating to the config path not being set as R/W Slave. When i try to edit the docker container to fix this the config is the one path that i dont have the edit option next to in order to set this as required.

 

Is this something i should redefine myself by adding a new path and leaving the existing config path empty? obviously as the edit and delete button arent available on the config as standard this isnt an option.

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