In the previous blog, we were talking about Server Virtualization, which allows us to run multiple Virtual Machines on it. Total number of Virtual Machines which can run on a single Physical Server depends on size of the Virtual Machine and Physical resources (CPU and Memory) on the Physical Server. If the Physical Server goes down, that will fail all the running Virtual Machines.
Even I have seen some customers who just Install ESXi and run plenty of critical Virtual Servers on it and say they are on Virtualization. I tell them, they are on Virtualization but with risk!!! If the physical server fails, they will lose access to Running Virtual Machine. Just Virtualizing is like utilizing 10% benefits of Virtualization. Now, to address these multiple Virtual Machines Failure, there is Management software called vCenter Server.
vCenter Server is installed on Windows Server Operating system like server 2008 R2 and it manages all the hosts and Virtual Machines from one place. It is just not used for managing all the Virtualized Servers and hosts, it provides various distributed Services like vMotion, HA, DRS, FT etc.
People who do not like vCenter Server on Windows, they can deploy vCenter Server Appliance (SUSE Linux based), it is preconfigured with Database and Services like Single Sign On, Inventory services. There is no difference in functionality just that one is running on Windows platform and other on Linux.
A database is mandatory for vCenter Server, the embedded Database which comes with vCenter Server is suitable for 5 Hosts and 50 Virtual Machines on Windows Platform and for vCenter Server Appliance (vCSA 5.5) it supports upto 500 Hosts and 5000 Virtual Machines, for any environment bigger than 5 Hosts and 50 Virtual Machines, a full blown Database is mandatory.