Configuration of HeaderDigest and DataDigest elements for software iSCSI

1. Open the /etc/vmkissci.conf file. For ESX, you can access the file from the service console. For ESXi, use the vifs Remote CLI to retrieve the file.
2. Edit the file. You can add lines or replace lines that start with #HeaderDigest= and #DataDigest= , if they exist already.

To globally enable CRC32C digest checking for the header or data part of iSCSI PDUs, use:

HeaderDigest=always
DataDigest=always

To globally disable digest checking for the header or data part of iSCSI PDUs, use:

HeaderDigest=never
DataDigest=never

To globally allow the targets to control the setting of the digest checking, with the initiator requesting a preference of enabling the checking, use:
HeaderDigest=prefer-on
DataDigest=prefer-on

To globally allow the targets to control the setting of the digest checking, with the initiator requesting a preference of disabling the checking, use:
HeaderDigest=prefer-off
DataDigest=prefer-off