Need help/recommendations for converting 4 drives from reiserfs to xfs.

Hi everybody,

I'm in the process of converting 4 drives from reiserfs (deprecated) to xfs. I thought it would be simple (switch drives and rebuild) but it seems that Unraid will rebuild the drive in reiserfs, which makes sense but is not a good news for me. I also want to take this opportunity to update these disks by replacing them with larger disks. I want my data to be as safe as possible during this update. I've read a lot of stuff but I think that I'm trying too hard to simplify the transition so I can do it in the least amount of time and effort and I'm lost. So, I need some help.

Let's start with my array :

Device      Identification                                    FS               Size

Parity      WDC_WD40EFRX-68N32N0 - 4 TB

Disk 1      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs      3 TB

Disk 2      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs      3 TB

Disk 3      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs      3 TB

Disk 4      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs      3 TB

Disk 5      WDC_WD30EFRX-68AX9N0 - 3 TB      xfs            3 TB

Disk 6      WDC_WD40EFRX-68N32N0 - 4 TB      xfs            4 TB

Disk 7      WDC_WD40EFRX-68N32N0 - 4 TB      xfs            4 TB

Disk 8      WDC_WD40EFZX-68AWUN0 - 4 TB      xfs            4 TB

Then, I've upgraded my parity so I can put bigger drives than 4 TB in my array and I've added a second parity drive. So now, my array look like this :

Device      Identification                                    FS               Size

Parity      HGST_HUH721010ALE604 - 10 TB

Parity 2   HGST_HUH721010ALE604 - 10 TB

Disk 1      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs         3 TB

Disk 2      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs         3 TB

Disk 3      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs         3 TB

Disk 4      WDC_WD30EFRX-68AX9N0 - 3 TB      reiserfs         3 TB

Disk 5      WDC_WD30EFRX-68AX9N0 - 3 TB      xfs               3 TB

Disk 6      WDC_WD40EFRX-68N32N0 - 4 TB      xfs               4 TB

Disk 7      WDC_WD40EFRX-68N32N0 - 4 TB      xfs               4 TB

Disk 8      WDC_WD40EFZX-68AWUN0 - 4 TB      xfs               4 TB

So now, I have my old 4 TB parity on hand + 3 others 10 TB drives, all emptied and precleared. So, I can transfer and move files around if needs be. The expected result at the end of all this would be :

Device      Identification                                    FS               Size

Parity      HGST_HUH721010ALE604 - 10 TB

Parity 2   HGST_HUH721010ALE604 - 10 TB

Disk 1      HGST_HUH721010ALE604 - 10 TB      xfs               10 TB

Disk 2      HGST_HUH721010ALE604 - 10 TB      xfs               10 TB

Disk 3      HGST_HUH721010ALE604 - 10 TB      xfs               10 TB

Disk 4      WDC_WD40EFRX-68N32N0 - 4 TB      xfs               4 TB (my old replaced parity drive)

Disk 5      WDC_WD30EFRX-68AX9N0 - 3 TB      xfs               3 TB (no change)

Disk 6      WDC_WD40EFRX-68N32N0 - 4 TB      xfs               4 TB (no change)

Disk 7      WDC_WD40EFRX-68N32N0 - 4 TB      xfs               4 TB (no change)

Disk 8      WDC_WD40EFZX-68AWUN0 - 4 TB      xfs               4 TB (no change)

I've take a quick look on unBALANCE and rsync, which, I think, might help me to get the job done. Of course, if possible, I would like to preserve parity during the transition but I'm open to suggestions, even if they're a bit risky.

Thank you everyone for your help.