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Modifying queue depth and timeouts
12 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
4.2.2 Software iSCSI initiator
Similarly, for the software iSCSI initiator, complete the following steps:
1. Set the queue depth to 255 (example shown):
esxcli system module parameters set -m iscsi_vmk -p iscsivmk_LunQDepth=255
2. If the login timeout is not already set to 5 seconds (the default), change it to 5 seconds (example
shown):
- Determine the iSCSI adapter name:
esxcli iscsi adapter list
- Set the login timeout parameter:
esxcli iscsi adapter param set –A=vmhba37 –k=LoginTimeout –v=5
Note: The recommended LoginTimeout value has recently changed from 60 back to the VMware default of 5.
If the ESXi host connects to both PS Series (60 recommended) and to SC Series (5 recommended), the
timeouts should be individually set at the discovery address level within the ESXi iSCSI initiator.
3. Reboot the ESXi host for the change to take effect.
4. To verify the settings, use the following commands:
esxcli system module parameters list -m iscsi_vmk
esxcli iscsi adapter param get –A=vmhba37
Note: In earlier versions of ESXi 5.x, the option to set the login timeout parameter is not available. To enable
the login timeout parameter, it may require applying the patch as described in VMware KB article 2007680.
4.2.3 SAS HBAs
For SC Series arrays that have SAS front-end ports, use the following recommendations.
For the mpt3sas, use all the default driver module settings.
For the lsi_msgpt3, change the following module parameter setting as recommended by the Dell KB article
Driver Compatibility with Front End SAS Connectivity.
esxcli system module parameters set -p issue_scsi_cmd_to_bringup_drive=0 -m
lsi_msgpt3
Caution: The driver module in use differs between ESXi versions. Review the Dell KB article Preparing
VMware ESXi Hosts to Attach to SCv20x0, SCv30x0, SC4020, SC5020 SAS Arrays for more information.