Your data directory is not writable (zfs snapshot)

Hello all.

I’ve mounted a nfs (zfs) snapshot for backup reasons as the data directory (i know i must have the right database snapshot too). This snapshot is read-only. Nextcloud now complains: " Your data directory is not writable". Well ok, i know that. So here is my question. Can I force nextloud to somehow accept the read-only date directory? Otherwise i have to copy the whole nfs snapshot. This would take a lot of time.

thanks and cheers