What sort of disk is hdisk10?

If it is a SCSI or SSA disk it might be that the disk is nearing the end of its lifetime. When AIX formats a disk it puts aside some of the blocks for error correction. Once a disk block becomes unreadable ("bad block") its contents are being swapped to one of the spare blocks and in errpt you see that reflected by a "hdisk temp error" (i think it is "hdisk error 3"). When all the spare blocks are used the disk will start to have unrecoverable read errors, which will be documented in the errpt with a "hdisk error 4".

Post here the output of "errpt -a | head -50" to let us examine the details.

I hope this helps.

bakunin