I noticed a discussion on an internal mailinglist which mentioned the advanced setting “Disk.UseDeviceReset” as it is mentioned in the FC SAN guide. The myth that you need to set this setting to “0 “in order to allow for Disk.UseLunReset to function properly has been floating around too long. Lets discuss first what this options does. In short, when an error or SCSI reservations need to be cleared a SCSI reset will be send. We can either do this on a device level or on a LUN level. With device level meaning that we will send it to all disks / targets on a bus. As you can imagine this can be disruptive and when there is no need to reset a SCSI but this should be avoided. With regards to the settings here is what will happen with the different settings:
Disk.UseDeviceReset = 0 & Disk.UseLunReset = 1 --> LUN Reset
Disk.UseDeviceReset = 1 & Disk.UseLunReset = 1 --> LUN Reset
Disk.UseDeviceReset = 1 & Disk.UseLunReset = 0 --> Device Reset
I hope that this makes it clear that there is no point in changing the Disk.UseDeviceReset setting as Disk.UseLunReset overrules it.
ps: I filed a document bug and hope that it will be reflected in the doc soon.