If you use LVM, then it is possible to quiesce the DB storage using LVM snapshots, then take the backup of the snapshot. LVM has the ability to provide RAID, if the PV/VG and LV are setup on multiple disks at creation time. LVM uses mdadm internally.

Or you can do the mdadm stuff to make a RAID device, then layer LVM over it.

Or you can use ZFS which can do RAID-whatever and supports snapshots.

Alas, all the documentation for these is written for admins.