SC Storage Customer Notification: Driver Compatibility with Front End SAS Connectivity

Issue:
In the Dell EMC Storage Compatibility Matrix, the 6.5 VMWare ESXi version is tested / supported with SAS front end connectivity. SAS driver "lsi-msgpt3" Version 12 and Storage Center OS (SCOS) Versions 7.2.x and 7.3.x were included in this tested and supported solution. However, upgrades to VMWare ESXi 6.5 U1, 6.5 U2, and 6.7 automatically install updated lsi-msgpt3 SAS drivers, such as Version 16.  Without manual intervention of configuring a module parameter on the driver, lsi-msgpt3 versions greater than 12 do not work properly (e.g., rebooting host sees LUN capacity of 0 bytes, lose access to SAS Front End volumes upon controller failover, PSOD kernel dumps) with ESXi versions using this updated driver and SCOS. This most notably impacts ESXi 6.5 and 6.7, however if this newer driver is used on ESXi 6.0 (which is not default driver) this would also apply.

Recommendations:

If you are utilizing SAS connectivity between Storage Center and ESXi hosts utilizing the lsi-msgpt3 driver (ESXi 6.5+ typically), then the best practice setting is to modify the module parameter as described below for all versions of the lsi-msgpt3 SAS driver.  It is a requirement for any version greater than 12.  This updated Best Practice Settings can be found in Dell EMC SC Series Best Practices with VMware vSphere 5.x–6.x. Please keep in mind this change requires a reboot of the host to take effect.

Steps to configuring the module parameter on the SAS driver 

1. List out the module parameter values

esxcli system module parameters list -m lsi_msgpt3

2. Modify the issue_scsi_cmd_to_bringup_drive module parameter

3. Validate that the module parameter value has been modified with the list command in Step 1.

4. Reboot the ESXi host for the changed value to take effect.