hypervisor and docker only. rationale inside.

[erlipton]

Please be friendly, I admit I am noob. 

 

I have a spare license and a spare micro form factor dell. For obvious reasons, 3.5 drives are out of the question; I have space for an m.2 and a 2.5. I have 2 SSDs, 1TB 2.5 and 1TB m.2. I would like to (I know it's not purely meant for) use it as a Docker and Hypervisor only. I am a little confused on how to configure the drives and shares to achieve this:

 

Use the m.2 drive (can I use Cache?) as a primary host to the dockers and VMs.

Use the 2.5 drive (on the array?) leveraging mover to create nightly backups of my host drive.

 

My question is, how to I keep the data on the cache drive if I am moving it to the array? I was trying to research Copy-on-write, but the whole thing about btrfs was a bit confusing to me, and generally seemed like people wanted to avoid the topic of COW.

 

Thank you KINDLY for helping your friendly neighborhood noob.

[ChatNoir]

The array is not a great idea for SSDs as then would not benefit from scrub TRIM. Unless you are thinking about a 2.5" HDD and your idea could work for drives assignement.

 

In any case, there are solutions if you are on a full SSD setup.

1. You could assign one or both drives as unassigned devices (with the plugin conveniently named as such).
2. But I think you might want to look at the 6.9 branch (actually in beta). It provides better configuration for SSDs and several disk pools.

 

Note : Unraid requires an array. It doesn't have to be a proper disk, you can assign an usb stick, never use it and be done with that.

 

For the back up, I think you would have to set up a back up script to manage the backups (maybe a plugin already offers that depending of your actual need). I am pretty sure it is doable and that you can find some help around here.

Edited October 17, 2020 by ChatNoir
correct mistake

[erlipton]

12 hours ago, ChatNoir said:

The array is not a great idea for SSDs as then would not benefit from scrub. Unless you are thinking about a 2.5" HDD and your idea could work for drives assignement.

 

In any case, there are solutions if you are on a full SSD setup.

1. You could assign one or both drives as unassigned devices (with the plugin conveniently named as such).
2. But I think you might want to look at the 6.9 branch (actually in beta). It provides better configuration for SSDs and several disk pools.

 

Note : Unraid requires an array. It doesn't have to be a proper disk, you can assign an usb stick, never use it and be done with that.

 

For the back up, I think you would have to set up a back up script to manage the backups (maybe a plugin already offers that depending of your actual need). I am pretty sure it is doable and that you can find some help around here.

My understanding, and it's a primitive understanding, so please correct me if I am wrong... the only reason SSDs are not recommended for array is because when using TRIM for parity, it can get a little messy. But... in my scenario with the hardware I have to work with, I wont be doing parity.

 

Fantastic thought with the usb stick as the array. Didnt think of that; mad genius. 

 

Really looking forward to making these ambitions a reality. Thanks for your help so far!

Edited October 17, 2020 by erlipton

[ChatNoir]

Your are right, TRIM, not scrub ... I should not go in technical details I do not know that well so soon in the morning... 

Anyhow, glad I could help.

[Ford Prefect]

Yes, but remember, that a parity is is not required in an array. I had a similar usecase, running a smaller 250GB SSD as the only array disk and 2x1TB NVMe-PCIe as Cache-Pool, for Docker/VMs. My box is an embedded/IPU system with i5-7200u, 6xIntel-NIC, running a Router VM (pfsense) and dockers.

[erlipton]

55 minutes ago, Ford Prefect said:

Yes, but remember, that a parity is is not required in an array. I had a similar usecase, running a smaller 250GB SSD as the only array disk and 2x1TB NVMe-PCIe as Cache-Pool, for Docker/VMs. My box is an embedded/IPU system with i5-7200u, 6xIntel-NIC, running a Router VM (pfsense) and dockers.

Would love more info on this. Were you running btrfs raid 1 or 0? what did you use the 250 for besides being the array drive, i;e did it serve a purpose? 

 

Being that my 2.5 and my m.2 have fastly different speeds, I didnt want to put in a btrfs cache pool. rather, nightly backup sort of mode.

 

Knowing my goals and my setup, how would you recommend I proceed? TIA

[Ford Prefect]

...it's a setup in a holiday home.
The SSD actually was a spare part, at that time. We are using it as a long term cache for movies and music, when being on site during vacation (pre-filling it from the main storage server at home), so wear and tear is minimal and data loss is not an issue, should it go down. Main purpose of the box is internet firewall and dockers for all sorts of smart home gizmos.

Both Cache NVMe disks are identical and therefore form a btrfs pool, raid 1.
Mixing models or technologies is something I wouldn't recommend, like you already found out yourself.

The reason that I used unRAID was that I have a similar setup at home and using GRE-Tunnels (along with zerotier for backup) to connect both sites.

I your case you should decide if you can live without redundancy. Another option maybe us to go for the zfs plug-in, an use this instead of cache for VMs and dockers.



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[erlipton]

On 10/18/2020 at 12:08 AM, Ford Prefect said:

I your case you should decide if you can live without redundancy. Another option maybe us to go for the zfs plug-in, an use this instead of cache for VMs and dockers.

Yes, I am fine with foregoing redundancy. I want a backup mechanism though, mixing models shouldnt be an issue with that. So, my VM and Docker to live on the NVMe cache drive, and 2.5 SSD on the array, I can somehow set up a recurring back up to the array from cache? This is what I need help understanding, how to accomplish this

[Ford Prefect]

I am not aware that this kind of use-case will work with an intelligent setting of the Cache drive in the share config.

Maybe there are methods or even community-Apps already available.

If there are not, actually I think using the ZFS plugin and creating snapshots (from CLI) would work best here.