CKPT process keep hanging

Hi all, we just recently create a 10g (10.2.0.4) RAC on HPUX however, we find that the CKPT process keeps hanging the database. Everytime this happens, when I check dba_waiters I always see CKPT process blocking other sessions with RO locks. Drilling down even more, I see CKPT is timing out with rdbms ipc message.

I opened a tar with Oracle for a few days now (not useful so far) and they still looking for the culprit however they think that it my be disk i/o issue. Has anyone seen this before? Thanks