Data Pooling with MergerFS

matthias80 · 1. Februar 2021

Hello everyone.

After I didn't get any answers in German, I'll try my luck again in English ...

During my new installation I tried the two plugins Union FS and Merger FS.

Unfortunately, I am not getting the result I wanted.

For each of my main directories I would like to specify whether the data is distributed over several disks or specifically stored on one disk.

Disk 1

/Medienspeicher/Bilder/2020 -> All Pictures of 2020

Disk 2

/Medienspeicher/Bilder/2021

Disk 3

/Medienspeicher/Bilder/2019

E.g. Photo folders can be distributed, but the whole Photos / 2020 folder.

Music or documents could be placed discreetly on a disk.

I want to user the spin down feature on the disks,

therefore sensible data storage is important.

With UnionFS I couldn't do that, with Merger FS I don't know what to enter in the path.

Can someone help me with this.

Many Thanks

Regards

Matthias

Adoby · 1. Februar 2021

I don't think it is possible to have different storage policies for separate folders.

However, if you create a pool with existing files in folders, the files remain where they are. Unless you move/copy/modify the files. Or balance the pool.

One possible option then is to use a policy that does not preserve the path and regularly run a script that move files you have changed back to the right HDD. I think rsync would be perfect for this, but some testing would be needed to verify that Move files from the wrong HDD to the right. Perhaps as part of you creating normal backups of your data.

(Warning: When moving files in a mergerfs between the pool and individual HDDs it is easy to delete files by mistake! That is because often when you move a file you use a copy-delete method. And the delete may delete both copies if the paths match...)

Another option could be to create two separate pools. One that preserves existing paths and one that doesn't.

matthias80 · 1. Februar 2021

Ok, thanks for your awnser.

That with the different pools sounds like a practicable way for me.

But for this I think the best plugin would be Merger FS.

Can someone tell me how the paths have to be structured that have to be entered there for each pool

e.g. /srv/dev...xxx..xxx..disk1/mediastorage/pictures ???

ryecoaaron · 1. Februar 2021

Zitat von matthias80

I don't know what to enter in the path.

If you enable the Absolute Path column (click arrow in the column header) in the Shared Folders tab, you see the path you need to use. And no, you can't cut&paste and there is no way to fix that. Put each absolute path on a new line in the mergerfs folders plugin.

matthias80 · 1. Februar 2021

Ok thanks that worked before.

But I don't have to create the pool in advance to then select it when sharing folders.

ryecoaaron · 1. Februar 2021

Zitat von matthias80

But I don't have to create the pool in advance to then select it when sharing folders.

Not sure what you mean. If you want to create sharedfolders from the mergerfs pool, the pool has to exist.

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