Difference Between Vpshere Version

	vSphere 4.0	vSphere 4.1	vSphere 5.0	vSphere 5.1	vSphere 5.5	vSphere 6.0
Hypervisor	ESX & ESXi	ESX & ESXi	ESXi	ESXi	ESXi	ESXi
CPUs per host	64	160	160	160	320	480
RAM per host	1 TB	1 TB	2  TB	2  TB	4 TB	12 TB
vCPU per VM	8	8	32	64	64	128
vMEM per VM	255 GB	255 GB	1 TB	1 TB	1 TB	4 TB
VMDK Size	2TB	2TB	2TB	2TB	62 TB	62 TB
Cluster Size	32	32	32	32	32	64
FT Max vCPU	1 vCPU	1 vCPU	1 vCPU	1 vCPU	1 vCPU	4 vCPU
VM Hardware Version	7	7	8	9	10	11
VMFS Version	3.33	3.46	5.54	5.58	5.60	5.61
Features	– Distributed Switch – Update Manager – Fault tolerance – Host Profiles – Storage vMotion – Linked Mode – Enhanced vMotion – Compatibility – Distributed Power Management – Hot Add VM CPU/Memory – VMDirectPath – VMXNET3	– Boot from SAN – Scripted Installation – Storage I/O Control – DRS Host Affinity – Memory Compression – Array Integration – Network I/O Control	– Auto Deploy – Storage DRS – vSphere Storage Appliance – Profile driven storage – vSphere Web Client – vCenter Server Appliance – ESXi Firewall	– Single Sign-On – Enhanced vMotion – Sparse Virtual Disks – Single-root I/O Virtualization – vSphere Replication – vSphere Data Protection – vShield Endpoint	– vSphere Flash Read Cache – Virtual SAN – Reliable Memory Technology – vSphere Big Data Extensions – vCenter Single Sign-On 2.0 – vSphere App HA – 40GBps NIC Support	– Virtual Volumes – vMotion across vSwitches – Cross vCenter vMotion – Native Linked Mode – Platform Services Controller – Certificate Authority (VMCA) – Content Library
Preferred Management	vSphere Client	vSphere Client	vSphere Client	vSphere Web Client	vSphere Web Client	vSphere Web Client
Authentication Management	–	–	–	Single Sign-On	Single Sign-On 5.5	Platform Services Controller
Backup Strategy	VMware Data Recovery (VDR)			vSphere Data Protection (VDP)
vMotion Support	– Boundary: Datacenter – Shared Storage required – max. 5ms RTT	– Boundary: Datacenter – Shared Storage required – max. 5ms RTT	– Boundary: Datacenter – Shared Storage required – max. 10ms RTT	– Boundary: Datacenter – max. 10ms RTT	– Boundary: Datacenter – max. 10ms RTT	– vMotion across vCenters – vMotion across vSwitches – max. 100ms RTT
Virtual SAN	–	–	–	–	VSAN 5.5	VSAN 6.0
HA Agent	AAM Automatic Availability Manager		FDM Fault Domain Manager
VAAI Primitives	–	– Atomic Test & Set – Cloning Blocks – Zeroing File Blocks	– Atomic Test & Set – Cloning Blocks – Zeroing File Blocks – UNMAP – Quota Exceeded Behavior – TP LUN Reporting – NFS Full File Clone – NFS Space Reservation – NFS Extended Stat – NFS Space Reclaim – NFS Fast File Clone
vCenter Type	Windows	Windows	Windows Linux (vCSA)	Windows Linux (vCSA)	Windows Linux (vCSA)	Windows Linux (vCSA)
vCSA Scale (vPostgres)	–	–	5 Hosts 50 VMs	5 Hosts 50 VMs	100 Hosts 3000 VMs	1000 Hosts 10000 VMs

ESxi host stuck at 2 %

Today I was working on ESxi host to change the power settings in BIOS of an HP server, while doing that I was placing Esxi host in Maintenance mode there were around 24 VM's on that host all are migrated to another host in that cluster except one and noticed maintenance mode stuck at 2%, so I was think may be that particular VM might be having CD/DVD is connected, to check that when I was right clicking the VM, edit setting option was disabled, so I logged on  to that Virtual machine to check any CD/DVD drive is connected or not nothing is connected, then verified all vMotion prerequisites all are good , so finally I had to migrated that particular VM manually by selecting migrate option then selecting another host in same cluster it migrated successfully with no issues then Exi host placed in maintenance mode without any issues. 

Solution: Migrate VM manually to another Esxi host in same cluster.