WriteSubrequestLength
Applies To: Windows 8, Windows Server 2012
The WriteSubrequestLength setting works with other settings in the Microsoft-Windows-SecureStartup-FilterDriver component to optimize BitLocker settings for PCs with hardware architectures such as System on a Chip (SoC). Do not use these settings for standard 32-bit or 64-bit hardware architectures.
These settings are intended for OEM manufacturing only. For specific guidance on using these settings, contact Microsoft.
Note
These settings only apply to Windows 8.
Values
WriteSubrequestLength is an integer value, in bytes.
The default value is 524288 (512 MB).
Valid Configuration Passes
offlineServicing
specialize
auditSystem
oobeSystem
Parent Hierarchy
Microsoft-Windows-SecureStartup-FilterDriver | WriteSubrequestLength
Applies To
For a list of the Windows editions and architectures that this component supports, see Microsoft-Windows-SecureStartup-FilterDriver.
XML Example
The following example specifies recommended values for Bitlocker optimizations on an x86 System on a Chip.
<component name="Microsoft-Windows-SecureStartup-FilterDriver" processorArchitecture="x86" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS" xmlns:wcm="https://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<BytesDecryptedInDiskRequestOverhead>262144</BytesDecryptedInDiskRequestOverhead>
<InPlaceCrypto>0</InPlaceCrypto>
<MaxCryptoRequestsPerIo>4</MaxCryptoRequestsPerIo>
<MaxDecryptRequests>0</MaxDecryptRequests>
<MaxEncryptRequests>2</MaxEncryptRequests>
<ModifiedWriteMaximum>4</ModifiedWriteMaximum>
<ReadDoubleBuffering>0</ReadDoubleBuffering>
<SlicedEncryptionInPlace>1</SlicedEncryptionInPlace>
<SlicedEncryptionMinSize>524288</SlicedEncryptionMinSize>
<SlicedEncryptionRequestsMax>1</SlicedEncryptionRequestsMax>
<WriteIoAggregateMaxSize>1048576</WriteIoAggregateMaxSize>
<WriteIoAggregateMinSize>1048576</WriteIoAggregateMinSize>
<WriteSubrequestLength>524288</WriteSubrequestLength>
</component>