HP 3PAR RedHat and Oracle Linux Implementation Guide

Storage arrays that have a smaller target port queue depth of 512. These situations can be
mitigated by reducing the values for parameters node.session.cmds_max and
node.session.queue_depth on each host that shares the array target port.
9. As an option, you can also enable the Header and Data Digest for error handling and recovery
within the connection.
Typically, whenever a CRC error occurs, the SCSI layer tries to recover by disabling the
connection and recovering. However, by enabling the header and data digest, individual
iSCSI PDUs will be retried for recovery for those connections missing the data (CRC Error) or
missing a PDU or sequence number (Header Digest). If the recovery does not occur, then the
low level SCSI recovery will be initiated. The Header and Data Digest is optional since the
SCSI layer will still perform CRC error recovery at the session level rather than at the PDU
level.
CAUTION: Enabling Header and Data Digest will cause some I/O performance degradation
due to data checking.
You can enable the Header and Data Digest by adding the following lines in iSCSI
configuration file /etc/iscsi/iscsid.conf:
node.conn[0].iscsi.HeaderDigest = CRC32C
node.conn[0].iscsi.DataDigest = CRC32C
NOTE: In order for the parameter changes to take effect, restart the iSCSI service after the
change.
10. Enable any other configuration changes such as CHAP authentication. For details, see “Setting
the Host CHAP Authentication on the HP 3PAR StoreServ Storage” (page 83).
Setting Up Hardware iSCSI for RHEL 6 or RHEL 5
Use the BIOS to add IP addresses, and use the OneCommand Manager GUI or the hbacmd utility
to configure hardware iSCSI. For information about setting up and configuring hardware iSCSI,
see the OneCommand™Manager Command Line Interface Version 6.1 User Manual, which is
available at the following website:
Emulex
Setting IP Addresses Using BIOS
1. Using the system BIOS, add the IP addresses (Figure 4 (page 61)):
60 Configuring a Host with iSCSI