Monitoring with APConsole showed the following.
Following metalink notes are related to this wait event.
High waits for "ksfd: async disk io" [ID 1326634.1]
Bug 8660422 - "unspecified wait event" and/or "ksfd: async disk IO" after applying patches that include fix for Bug 7510766 [ID 8660422.8]
This database has the PSU 11.1.0.7.6 applied. Blog post will be updated when PSU 11.1.0.7.7 or the patch 8660422 is applied.
Update on 19th November 2011
After October 2011 PSU (11.1.0.7.9) was applied ksfd: async disk io waits disappeared. Graph (generated with ADMon)below shows the waits for two week period. Wait was happening daily on both or at least one instance (this was a two node RAC) but stopped since the applying of the patch (Patch was applied on 17th).
