This article provides steps to handle the IO failures seen in guest VM in case of degraded SW RAID-1.
Symptoms:
As part of setting up ESX for supporting disk mirroring at VM, it is recommended to enable the vmx options using the below parameters for releases below 6.7:
scsi0.returnBusyOnNoConnectStatus=FALSE
scsi0.returnNoConnectDuringAPD=TRUEFor more information, see
Set Up Dynamic Disk Mirroring.
In 6.7 release, when the SW RAID-1 in VM is put into degraded mode by failing a disk, the windows GOS may still see IO failures based on the HBA and/or the driver for the HBA.