Huge number of alert log entries: 'WARNING: IO Failed...' 'WARNING: failed to read mirror side 1 of virtual extent ...' (Doc ID 1274852.1)

https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=524859161269529&id=1274852.1&displayIndex=1&_afrWindowMode=0&_adf.ctrl-state=mahixz68x_159#SYMPTOM

参考MOS Doc ID 1274852.1 Check:

1) ASM side:

* Make sure the ASM instance remains up and running, despite of these entries/messages.
* Verify that all ASM disk groups remain mounted and have no offlined ASM disks.
* Overall, the ASM instance is functional (one can connect to it, run queries on the various v$asm% views, like: v$asm_diskgroup, v$asm_disk)

2) The database remains open and operational (no outage).

3) Storage level:

* The sysadmin, storage admin, and storage vendor has verified no errors in the OS system logs nor any other storage related logs, in regards to any of the disks or devices utilized by the ASM disk groups.

Furthermore, they have ran all due IO and hardware diagnostics on these devices/disks and they found no real IO or hardware related issue.

4) After all above checked okay, then this is related to Bug:10051315 , Bug:10055063 and Bug:10422126 which fix is included in 11.2.0.3

就是啥问题也查不出来，io高会出现，io低也会出现