#Vmware vsphere 6.5 lock out time windows

#Don't change anything beyond this point. You can easily set this for a LUN on an ESXi host with the following commands: ESXi basically wonвЂ™t scan the device during the boot process anymore. This setting just tells ESXi that there is a permanent SCSI reservation on the LUN, so it can be skipped during the boot process. This setting is called вЂњperennially reservedвЂќ. Our hosts have over 40 RDMвЂ™s so that took way to long.ДЇortunately, this can be fixed by setting an ESXi local device parameter on the LUN. In this KB VMware says that if you have 10 RDMвЂ™s the boot process is already 30 minutes (excluding physical hardware boot times).

Because of this the ESXi host cannot interrogate the LUN during the boot process and has to wait for a device scan timeout, which takes a long time. This however is a problem for RDMвЂ™s used in MSCS clusters because they have a permanent SCSI reservation allocated to them. And that was the problem! During the boot process, ESXi scans the so-called storage mid-layer and attempts to discover all devices presented to an ESXi host during the device claiming phase.

#Vmware vsphere 6.5 lock out time windows

Shortly after investigating this I remembered that these hosts have LUNвЂ™s being used as physical Raw Device Mappings (RDM) on Windows MSCS clusters. Checking the console it seemed to be stuck on the вЂњvmw_vaaip_cx loaded successfullyвЂќ message in the hypervisor boot screen. The host seemed fine to me after checking the hardware and configuration. We actually didnвЂ™t really notice this in theД«eginning, until we added hosts to the existing cluster and the reboot for that Have been having (extremely) slow boot times for a couple of hosts that weвЂ™veД«een using for a new customer.