Help understanding Unraid file path for VM instances?

[iwearshoes]

I have searched the forum and this seems to be an issue that others have come across, however the fix for their problems does not work for me.

 

Essentially I am going to start with my understanding of how the Unraid file tree is structured and feel free to correct me if I am wrong anywhere here:

My understanding is that Unraid creates a working directory in memory upon booting, using this directory to manage all the system files, however the file structure for the array is stored on the data drives?

 

I have limited experience with linux, so perhalps these are dumb questions, but at the root level, when viewing

ls -a

that is showing me the system hidden files in memory correct?

 

I ask as when attempting to setup virtual machines, every necessary file path is listed as "file path does not exist"

this occurs for the default paths of:

mnt/user/system/libvirt

mnt/user/domains

mnt/user/isos

 

so in theory can I not just mkdir the needed file tree? is mnt suppose to exist from the root level? (i.e. #root/mnt/user/etc....) - but if it is supposed to be created on boot, what is preventing it from being generated?

 

technical details: Dell r620 server (384gb ram, 20-core-40 thread xenons, 10TB storage)

 

[Energen]

26 minutes ago, iwearshoes said:

this occurs for the default paths of:

mnt/user/system/libvirt

mnt/user/domains

mnt/user/isos

Those would all be wrong to start... because linux is very specific on the format of things...  there's no such thing as mnt/user because it would actually be /mnt/user/ with a preceeding forward slash.. maybe you just left that out while writing and actually know that already but figured I'd just point that out in case...

 

27 minutes ago, iwearshoes said:

so in theory can I not just mkdir the needed file tree?

No, everything exists already.

 

28 minutes ago, iwearshoes said:

is mnt suppose to exist from the root level? (i.e. #root/mnt/user/etc....)

No, /mnt/ is not under /root/.

 

Open a new console window, you might see root@TOWER:~!# assuming your user name is root and TOWER is your Unraid name.

 

type ls -- you probably only see mdcmd@, right?  This is your root directory.. it's not really used for anything at this point.. that I'm aware of.

 

type cd /boot and then ls --- that's your flash drive.  you shouldn't really do anything here, just showing you a location.

 

now type cd /mnt and ls -- now you see your disks.

type cd user and ls -- now you see your shares.

from /root you'd type cd /mnt/user to get to your shares

 

So in the case of creating a VM, I'm not actually sure what your problem is .... in the template you'd select an existing iso which would look like /mnt/user/isos/ubuntu-20.04.1-desktop-amd64.iso

 

 

[iwearshoes]

Thanks for the reply, that makes a lot of sense. The extent of my bash/shell knowledge is installing dev language packages and libraries and git - so anything helps.

 

The forward slash does exist before all of the paths, I never altered the path, just left them as default. Yet even when I boot into gui mode on the local machine under setting>vm settings all of those path fields are flagged as "! folder does not exist" and if I go to the VM tab there are no options just and error saying "! Libvirt does not exist", libvirt is a KVM thing right? Is it possible the KVM packages are not being installed properly? 

[JonathanM]

Describe your hardware.

[iwearshoes]

1U Dell PowerEdge r620, 10x 1TB drives, 2x 10-core 20-thread Xenons, 384gb DDR3 - initially what I read said that Unraid wouldn't be able to see the drives through the SATA controller, but that was no problem once I set them up properly in the BIOS, only issue I'm having now is this path issue for VM functionality.

 

EDIT: Not sure if it matters, the Unraid is booting from a SanDisk USB drive on the internal motherboard USB.

 

Edited October 1, 2020 by iwearshoes
More information

[JonathanM]

How do you have those drives assigned and formatted?

[iwearshoes]

From the main gui window I configured it as:

1x Cache

2x Parity

7x Array

I used the bios controller to create an independent virtual disk with an independent disk group for each drive.

 

The drives were all new, so I haven't done a new format on them, I didn't know it was necessary since Unraid identified their size and information properly.

[JonathanM]

Do the drives show free space available in the main gui tab?

[iwearshoes]

oooh - Wow - not sure how I overlooked that - Yeah it is telling me each drive is  "undefined partition" in the free space column.

 

Guess I saw all green lights and drive size and thought I was good.
 

[iwearshoes]

26 minutes ago, jonathanm said:

Do the drives show free space available in the main gui tab?

A quick question related to this, I'm going to reset the entire configuration - does Unraid have a disk utility tool to automate drive formatting? Or is my best bet just to go to the link for each drive and set the file structure individually, also are there any recommended configurations for Format/file structure for setting up VMs? Data Security is not really an issue on these VMs so I don't need encrypted formats.

[JonathanM]

There is a checkbox and a button to format all unmountable drives at once on the main tab near the bottom. It will apply the default filesystem. You can make changes to the preferred file system globally in settings or on each individual disk.

 

To reset the drive assignments you will need to apply a "new config" in the tools tab.

 

Regarding file systems, there are some major changes in the beta that will apply to versions going forward, are you running 6.8.3 or 6.9 beta?

[iwearshoes]

Just now, jonathanm said:

Regarding file systems, there are some major changes in the beta that will apply to versions going forward, are you running 6.8.3 or 6.9 beta?

6.8.3

 

Thanks again for your help!

[JonathanM]

Are you using all SSD's? It makes a significant difference, in several ways.

[iwearshoes]

No - They are all mechanical - 3.5" server drives.

 

2.5" not 3.5"

Edited October 1, 2020 by iwearshoes
correction

[JonathanM]

I suspect you will be rather disappointed by the performance, given the slowness of those drives, but they should work ok.

 

If your hardware is rock solid, use BTRFS on everything. However, if the hardware is marginal, or you don't have a proper UPS in place, I'd use XFS. It seems more resilient to hardware crashes.

[iwearshoes]

They are 10k rpm drives, so  do you think that will help?, I am aware that in terms of bus I/O and ram speeds this is an 'old' system, however for the tasks these VMs will be performing, I will probably us 5% of the total available storage, and most of the I/O will can be measured in KB, So as long as they will run a super lightweight Debian build that's all I care about.

 

The hardware it's self is all top brand enterprise grade stuff, and the ram and drives are all new, it's just enterprise grade in 2014 - but 40 threads @ over 2.0ghz for under $1000 was hard to pass up.

[trurl]

1 hour ago, iwearshoes said:

I used the bios controller to create an independent virtual disk with an independent disk group for each drive.

RAID controllers are not recommended and possibly the cause of some of your issues.

[iwearshoes]

2 minutes ago, trurl said:

RAID controllers are not recommended and possibly the cause of some of your issues.

Agreed - It's worth my time to see if I can make it work though. There are few alternatives to Unraid that offer the kind of virtualization management I need, at a price I can afford.

If I can make it work as intended I will be happy to share the build notes as well.