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32 Dell EMC SC Series: Microsoft Windows Server Best Practices | 680-042-007
Replay Manager Explorer with Hyper-V Guest backup extension
4.8 Using BitLocker with SC Series volumes
Windows Server versions that support Microsoft BitLocker
®
have the native capability to encrypt volumes with
the BitLocker drive encryption utility. With BitLocker drive encryption, users can encrypt system and data
volumes to secure data residing on the volume. BitLocker makes use of the on-board Trusted Platform
Module (TPM), or a USB drive if TPM is not available to encrypt the system volume. Details on deploying
BitLocker can be found at the
Microsoft Windows IT Pro Center.
The BitLocker encryption process only encrypts the data contained on the volume. Any free space on the
volume is not encrypted. All blocks that comprise the data on the volume are changed, effectively creating a
new version of the data on the volume. As a result, the active snapshot on an SC Series volume will grow to
be the size of the total amount of data on the volume, regardless of the state of any historical snapshots on
the volume.
Keep in mind that the encryption process will result in re-writes of all the data on the volume to tier 1 by
default. On large volumes, this could cause tier 1 to become full. To minimize impact to the system, verify
there is enough space in tier 1 prior to applying encryption to accommodate the data in the volume. Do not let
the amount of data used exceed the space available on the system, otherwise the system could enter
conservation mode. If necessary, the encryption process can be prevented from consuming faster disks by
isolating the volume on a lower tier of storage by changing the storage profile on the volume.
In the following example, a snapshot was taken of an SC Series volume before BitLocker encryption was
applied. After the snapshot was taken, more data was added to the volume, increasing the total amount of
data on the volume to 38 GB. Approximately half of the data is stored in the active snapshot, and the other
half is stored in the historical snapshot.