Disk errors when copying

[Richard Tobin]

When copy between disks (ad10 ->ad8), I get errors:

ad10: WARNING - READ_DMA48 UDMA ICRC error (retrying request) LBA=435128800
ad10: FAILURE - READ_DMA48 status=51<READY,DSC,ERROR> error=10<NID_NOT_FOUND> LBA=435128800
g_vfs_done():ad10s2g[READ(offset=175562145792, length=131072)]error = 5

I don't get these errors just reading the data from ad10.  Is this
some kind of system error rather than a bad disk?  Is it a known problem?

(6.2 stable, SATA disks)

-- Richard