parted raid1 boot, raid1 root, raid10 lvm data

peter:~ # parted /dev/sda unit s print
Model: ATA ST3750640AS (scsi)
Disk /dev/sda: 1465149168s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start       End          Size         File system  Name      Flags
 1      2048s       4095s        2048s                     biosgrub  bios_grub
 2      4096s       2101248s     2097153s     ext4         boot      boot
 3      4530176s    172296191s   167766016s   ext4         primary   raid
 4      172296192s  1465149134s  1292852943s               primary

peter:~ # parted /dev/sdb unit s print
Model: ATA ST3750640AS (scsi)
Disk /dev/sdb: 1465149168s
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start       End          Size         File system  Name      Flags
 1      2048s       4095s        2048s        ext4         biosgrub  bios_grub
 2      4096s       2101248s     2097153s     ext4         boot      boot
 3      4530176s    172296191s   167766016s                primary   raid
 4      172296192s  1465149134s  1292852943s               primary