SSD <=> HDD Best Practice of disk management

[Schlotti]

Hi everyone.
I am new to Unraid. My setup is on a QNAP-NAS, with 2x 4TB SSD (1 Parity/1Data). I've installed 7 Dockers (several more pinned and coming soon), some plugins and 2 VMs.

Now I've read (i don't find the link right now), that using a SSD for Parity is a bad idea in Unraid.

So.... in my shelf is a 8 TB HDD.

 

What I've read sounds in my head like: Use the two 4TB SSDs as Cache and copy it every night to the HDD.

 

Now my question(s):

- What is the best practice with my setup as mentioned above?

- If it is neccessary for best practice to include the HDD and especially to use the SSDs as cache instead array: How do I change that?

 

Thanks a lot to anyone here.

 

Edited August 4 by Schlotti
Changing BP to best practice

[JorgeB]

1 hour ago, Schlotti said:

it is neccessary for BP

What is BP?

[Schlotti]

3 minutes ago, JorgeB said:

What is BP?

Sorry, I edited the post. It's "best practice". It's common usage in Veeam Community.

[JorgeB]

I would recommend setting up both SSDs as a mirrored pool, if you want to use the disk in the server set is as an array device without parity, but if it's gong o be used for backups, it would be better to have it external or on a different PC.

[Schlotti]

22 hours ago, JorgeB said:

I would recommend setting up both SSDs as a mirrored pool, if you want to use the disk in the server set is as an array device without parity, but if it's gong o be used for backups, it would be better to have it external or on a different PC.

Thanks for your answer.

Some questions about that: So, I should better reconfigure it from array with parity to cache with mirror? What is the best way to do it with keeping the configuration and data of the VMs and Dockers?

If I would like to have the 8 TB HDD for Backups, why is it better to keep it external? ( I would like to save Backups of Unraid Data/Dockers/VMs to it)

Best regards

Edited August 5 by Schlotti

[JorgeB]

Create a pool with one device, it should import the existing data, then add the other one to create a mirror.

[Schlotti]

21 hours ago, JorgeB said:

Create a pool with one device, it should import the existing data, then add the other one to create a mirror.

Umm... I don't get it.

I removed the parity drive, created a pool with 2 devices, selected the Ex-Parity Drive.... and then?
It says it's unmountable. And if I try to remove the main disc from the array, it's the same thing. Unmountable.

Could you help me with more details?

Edited August 6 by Schlotti

[JorgeB]

11 hours ago, Schlotti said:

I removed the parity drive, created a pool with 2 devices

No, as mentioned, create with one device.

[Schlotti]

1 hour ago, JorgeB said:

No, as mentioned, create with one device.

How could it import the data, when it's not mountable?

I am very confused. You said I should create a mirror pool.

Is there a manual to migrate this? I am working in IT, but I am new to UNRAID. I don't get what to do, to migrate the stuff from the shares from array to pool.

[JorgeB]

22 minutes ago, Schlotti said:

You said I should create a mirror pool.

No, I said:

21 hours ago, JorgeB said:

Create a pool with one device, it should import the existing data, then add the other one to create a mirror.

 

Post the output of

blkid

and the current diagnostics.

[Schlotti]

Ummm.... Okay. Let's start again.

Let's forget the HDD.

 

I have an array with 2 SSD (1 Data, 1 Parity).

In Unraid it's better to mirror it in a pool, right?

 

Normally array is XFS and Pool is btrfs FS and that sounds not compatible.
How can I move everything (all shares with all existing data etc.) without loosing data to a pool?
What should I do with which disk?

[JorgeB]

If it was using xfs you cannot create a mirror, I forgot to mention that, you can create a single device pool, assign the old parity to that pool, format it zfs, copy everything from the array ssd to the new pool, then add the array device to the pool to create a mirror.

 

P.S. if you are using 6.12 you will need to have at leas one array device assigned, that's no longer required with 7.0-beta