Seagate ST1000DL002-9TT153 dropouts

Installed ssh which allowed me to check what the Readynas systems made of upgrading from a 500GB mirror to a 1TB mirrored array.

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root@readynas:~# mdadm --detail /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Sat May 12 10:23:31 2012
Raid Level : raid1
Array Size : 4193268 (4.00 GiB 4.29 GB)
Used Dev Size : 4193268 (4.00 GiB 4.29 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent

Update Time : Mon Jul 2 13:41:22 2012
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0

Name : E0469AA09AE7:0
UUID : 15b6b5d0:b3940c96:f7896447:ac4a0bb8
Events : 257661

Number Major Minor RaidDevice State
3 8 1 0 active sync /dev/sda1
2 8 17 1 active sync /dev/sdb1
root@readynas:~# cat /sys/block/sda/queue/logical_block_size
512
root@readynas:~# cat /sys/block/sdb/queue/logical_block_size
512
root@readynas:~# cat /sys/block/sda/queue/physical_block_size
512
root@readynas:~# cat /sys/block/sdb/queue/physical_block_size
512
root@readynas:~#
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Whether the fact that it thinks it has a 4TB array and not a physical 1TB array is causing problems, or whether the Seagate internal translation of 4k block size to 512 byte block size is causing hiccups I do not know.
Any wise men out there? What should it say?

PS I meant Cinemastar not Videostar. Blame Buggles. They run up to 5C cooler than Deskstar at the same speed, and I had no problems using them in a FreeNAS mirror.