JSI Tip 5856. Dmio event errors, status 0xC000009A may cause corruption?

When you use dynamic disks, if your event log contains any of the following, it may lead to file system corruption:

Event Type:InformationEvent Source:dmioEvent Category:NoneEvent ID:29Date:MM/DD/YYYYTime:HH:MM:SS AM/PMUser:N/AComputer:       Computer_NameDescription:    dmio: Harddisk9 read error at block 445136247: status 0xC000009A Event Type:WarningEvent Source:dmioEvent Category:NoneEvent ID:35Date:MM/DD/YYYYTime:HH:MM:SS AM/PMUser:N/AComputer:       Computer_NameDescription:    dmio: Disk Harddisk9 block 445136247 (mountpoint F:): Uncorrectable read error Event Type:InformationEvent Source:dmioEvent Category:NoneEvent ID:30Date:MM/DD/YYYYTime:HH:MM:SS AM/PMUser:N/AComputer:       Computer_NameDescription:    dmio: Harddisk2 write error at block 411779656: status 0xC000009A

Status code 0xC000009A - STATUS_INSUFFICIENT_RESOURCES, is a lack of PTEs (Page Table Entries). This can occur on basic disks also, but Ftdisk.sys does NOT report it.

Lack of PTEs can be caused by:

- The /3GB setting in the Boot.ini file, which reduces the number of PTEs available to the kernel.

- The computer uses a storage adapter that can handle many simultaneous requests (up to 0xFF - 255 decimal), which requires additional PTEs.

- The computer is under memory pressure.

To workaround this issue:

1. If the computer is under memory pressure, add additional memory.

2. Reduce the concurrent I/O requests from your miniport driver by navigating to
HKEY_LOCAL_MACHINESystemCurrentControlSetServicesParametersDeviceNumberOfRequests.
Either delete NumberOfRequests, to cause the default of 16 to be used, or modify the REG_DWORD data value to be a number between 15 and 255.

3. Shutdown and restart.

NOTE: None of the Microsoft supplied drivers use NumberOfRequests.