Couple of questions (Auto-backup folders/accessing drives)

A. Yes. You can do it with Rsync, and the command line can be set in Scheduled Jobs for automation and keeping it in the GUI.

An example command line:
rsync -av --delete /srv/dev-disk-by-label-DATA1/Documents/ /srv/dev-disk-by-label-DATA2/Documents/

The left side is the source and the right side is the destination. This creates a simple mirror of the contents of the folder "Documents". --delete removes files in the destination that are not in the source. It might be best to leave --delete out during the first snyc.

B. I've never used this EXT reader. Install in on a Win10 box, plug in your EXT4 disk, and see what happens.

If you're not getting under-voltage warnings, the most likely "catastrophic" problem with an R-PI will be with the SD-card. You might consider cloning a copy of it in accordance with the OS backup section in this guide.

Zitat von YesThisIs

A) I have 2 different size external HDD's connected to it. Is there way to autobackup one shared folder (for example DATA-folder that i have created) to both drives, without mirroring with Raid1 both drives together? Only need this one folder to be backed up automatically to both drives.

You can also create an rsync job in the GUI of OMV: Services > Rsync > Add
The job can be scheduled at certain time or in certain intervals

Zitat von YesThisIs

B) In case my Pi dies, i recorn these are normal formated ext4-drives that i can plug into my Win10-device and load them with something like Ext2Read? Is there something i should consider in "catastrophic failure" happens to my Pi?

You can boot a Linux life distro on your windows machine and copy the files from the ext4 drives to your Windows drive.

Zitat von macom

You can also create an rsync job in the GUI of OMV: Services > Rsync > Add
The job can be scheduled at certain time or in certain intervals

That's a good point. I'm getting so used to setting a CL in Scheduled Job's, I forgot about using Rsync in the GUI, locally, with shared folders.

Zitat von YesThisIs

is OMV setup for specifically that Rasbperry Pi at the beginning?

Not sure what you mean by this.

Zitat von YesThisIs

Can i make an SD Card setup of OMV4, run it in 2gb and set it up. When my 4gb upgrade comes in mail, can i just swap the SD card from the 2gb to 4gb without an issue?

I'm not sure here, either. The recommended boot drive size is 8GB.

In any case, when using win32diskimager, you can go from a small card to a larger card with no problem. Going from large to small may be a problem. It might work if the option box "Read Only Allocated Partitions" is checked, but I haven't tested it. Since you'll only have two cards, if I were you, I wouldn't risk a test.

So, what I would do is:
- Clone your working card (the smaller) card to the larger card.
- Test the larger card in your R-PI (make sure it's working and all is good)
- Store the larger card - this is your backup.
- Use the smaller card for day to day use.
- Update the backup clone when you actually change something on your NAS, like adding a new share or a new service. (Meaning reclone the larger card, test it, and store it again.

BTW: I wouldn't update the clone, after minor software updates. The backup may be used if something goes wrong with an update. Only update when you change the function of your NAS.

Hope that helps