## Data Preparation

Data preparation is a process that converts the clear data on the disk to encrypted data and vice versa. When the SME Disk feature is enabled on an existing disk containing clear data, the existing clear data needs to be converted to encrypted data. The process can be done in two ways:

• With the host accessing the data. This is called as the online data preparation mode.

• With the disk that is inaccessible to the host. This is called as the offline data preparation mode.

Note Only offline data preparation mode is supported.

When the SME Disk feature is enabled on a new disk that does not contain prior data, the host I/Os read/write is decrypted or encrypted using a key. This encryption process is transparent to the application. For these disks, the data preparation process is not required.

Note Ensure you do not change the cluster configuration while data preparation is under progress and do not remove node or add a new node while data preparation is in progress.

For disks requiring data preparation, the user must have backed up data before starting conversion of clear data to encrypted data.

In an SME cluster, there can be multiple SME nodes handling the ITLs associated with a particular crypto disk. The multiple SME nodes encrypt or decrypt data written to or read from the crypto disk. However, the responsibility of the data preparation or rekeying for a crypto disk is assigned to one SME node which is the data preparation node. The cluster master handles the data preparation node based on the following:

• LUN visibility (report LUN, INQ, and so on) or accessibility (reservations)

• Target port affinity

• Load factor of the SME nodes

For signature mode, when converting a clear disk to crypto disk, the administrator must ensure that the reserved space of 64 MB at the end of the disk is available on the SME disk.

Note Disk Key Replication (DKR) must be disabled when performing data preparation on the source disk.