SnapRAID changing drive assignments arbitrarily ...?

Hope someone can solve this...

I am trying to get a fresh installation of OMV7 on new hardware. OS drive is an NVMe drive, and data drives are 4 HDDs. My process has been, install OMV to NVMe from USB drive during boot, switch to webGUI and download updates, install OMV-extras, downloaded SnapRAID and a few other plugins. Write ext4 file system to all 4 HDDs (dev/sda, sdb, sdc, sdd). Create shares /home in /sda, /media in /sdb, /backup, /docker and /quarantine (for ClamAV) in /sdc. Set up SnapRAID using /sda as data1 drive, /sdb as data2 drive, and /sdc as data3 drive, with /sdd as parity drive. It all went well, during all the setup, but a few minutes later I heard substantial HDD noise, and then just by luck happened to check the shares and their assigned drives had changed, and so had the drive assignments in SnapRAID -- I now have /home in /sdc, /media stayed in /sdb, /backup and /quarantine are on /sdd !!! and no shares on /sda, so I went to the SnapRAID setup and checked the drive assignments, /sda is now the parity drive ! instead of what I had assigned before which was /sdd. (I've omitted the "1" after each drive name, as in /sda1, etc. as there is only one partition per drive). EDIT -- I may have done a reboot in the middle of the process above... I did not keep that close of an eye...

I have gone through this twice, thinking that I had made a mistake assigning drives the first time around, but this is being done arbitrarily by OMV, and without user consent !

What if I had been setting stuff up with drives already containing data ? changing /sda from a data drive to a parity drive would have wiped out all my data in /sda !

Is what is happening OK ? I would like the shares I create to stay in the drives I chose, so that I know, if for some reason I have to unplug a drive that I know what its content is...

I am definitely NOT an expert, but this seems very odd to me... am I missing something ?

...or, perhaps the actual name, as in /dev/sda1 for a given drive is what changed, like to /dev/sdc1, and not the drive itself with its shares. Either way I think it is very confusing. Looking at the drives page, and the actual serial numbers on the drives, seems that this is what is going on, though not 100% sure. The drive that originally, at start of the installation, had the /sda label now has the /sdc label, /sdb remained the same, /sdc changed to /sdd, and /sdd changed to /sda. ...but why ? Is SnapRAID changing things ? I have to say I only noticed this after I finished setting up SnapRAID, maybe it was SnapRAID that did this, or maybe it was something else ? like SMB ? which I also set up before noticing all this.

Thank you both for the replies. Good to know the bits about the drives "labels" (like /sda, etc) changing on boot up. I used Fedora almost 20 years ago (Fedora 14) and I recall using the /dev/sda labels in /etc/fstab to specify mounting, so then the "labels" were pretty static.

Anyways, here is a screenshot of OMV in setting up a SnapRAID drive (I did use the plugin), the options given are indeed in the terms of /dev/sdX, not the UUID presented in the "absolute path" for the drives as presented in storage>shared _folders page. /dev/sdX is also used in the storage>files_systems page (screenshot 2). After taking screenshot 2, I rebooted, and indeed the /dev/sda labels changed, see screeshot 3. Thank you chente for pointing this out, while the UUIDs remained the same. I feel good now, and silly for having done a complete clean re-install when I first noticed this and thought it had been my fault in not picking the right drives based on the /dev/sdX labels.

Cheers