The HBA dropped offline and was re-detected, causing all disks connect there to be inaccessible:
pr 11 19:22:48 YAMATO kernel: md: disk1 read error, sector=0
Apr 11 19:22:48 YAMATO kernel: md: disk2 read error, sector=0
Apr 11 19:22:48 YAMATO kernel: md: disk3 read error, sector=0
Apr 11 19:22:48 YAMATO kernel: md: disk5 read error, sector=0
Apr 11 19:22:48 YAMATO kernel: md: disk6 read error, sector=0
Apr 11 19:22:48 YAMATO kernel: md: disk29 read error, sector=0
Rebooting should fix it but it might happen again, make sure it's well seated, sufficiently cooled, you can also try a different slot.