UseLunReset and UseDeviceReset VMware


If you are using a SAN attached ESX environment, make  sure:
Disk.UseLunReset is set to 1 (default = 1)
Disk.UseDeviceReset is set to 0 (default = 1).

The reason to disable the Disk.UseDeviceReset param is because it does a complete SCSI bus reset. All SCSI reservations will be cleared, not for a a specific LUN but for the complete device (being the whole SAN controller).

This could disrupt your SAN fabric. I would suggest setting the ESX host in maintenance mode and reboot it afterwards.

Alternatively, you can also set this via the Service Console by issuing the following commands:

esxcfg-advcfg -s 1 /Disk/UseLunReset
esxcfg-advcfg -s 0 /Disk/UseDeviceReset
service mgmt-vmware restart

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