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Host initiator settings
9 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
3 Host initiator settings
Ensure the initiator settings are configured in the ESXi host according to Appendix A: Required Adapter and
Server OS Settings in the latest Dell Storage Compatibility Matrix.
The current recommended settings are:
• QLogic
®
Fibre Channel card BIOS settings:
- Set connection options to 1 for point to point only
- Set login retry count to 60 attempts
- Set port down retry to 60 attempts
- Set link down timeout to 30 seconds
- Set the Execution Throttle to 255 (if available). The ESXi VMkernel driver module and DSNRO
control the queue depth. According to the QLogic support article, HBA Execution Throttle And
Queue Depth In A VMware Environment, the Execution Throttle variable is not used by the
QLogic driver.
• Emulex Fibre Channel card BIOS settings:
- Set the Node Time Out field, lpfc_devloss_tmo (formerly nodev_tmo) to 60 seconds
- Set topology to 2 for Auto Topology (point to point first)
- Set queue depth to 255. A queue depth of 255 allows the ESXi VMkernel driver module and
DSNRO to more conveniently control the queue depth.
• QLogic iSCSI HBAs: The ARP redirect must be enabled for controller failover to work properly with
iSCSI HBAs that support full hardware offload. Here is an example script for enabling ARP redirect:
esxcli iscsi physicalnetworkportal param set --option ArpRedirect –v=1 -A
vmhba4
Note: This command will not work with dependent hardware iSCSI adapters. This command replaces the
former esxcfg-hwiscsi command found in VMware KB Article 1010309. See the vSphere 5 Documentation
Center article, Reference to Replacements for Service Console Commands, for an explanation of the new
syntax.
• iSCSI initiator settings for delayed ACK: During periods of high network congestion in some
environments, iSCSI transfer latency may exceed acceptable levels. VMware recommends disabling
delayed ACK using the steps described in the article, ESX/ESXi hosts might experience read or write
performance issues with certain storage arrays, in the VMware Knowledge Base.
• SAS HBA card BIOS settings: For Dell Storage SCv2000 Series arrays configured with SAS front-end
ports, factory default settings within the card BIOS are recommended for SAS ESXi host HBAs.