So last month I had a meeting with IT staff and the GM, apparently the GM thinks that Virtualization means no need to have multiple server with same role. "I use virtualization so we can just restore the server using snapshots in case of server going down", it sound correct, but it won't change the most basic problem, downtime.
We have Virtualization so we can deploy server and use resource more efficient than having physical servers. But high availability requires planning and multiple server with the same role(a failover or load sharing group). Virtualization allows you to clone the server or restore from snapshots when hell break loose, but it will cause downtime(and non-stop angry phone calls). High Availability (with good planning and best practice) allows you to have 1 or more server down and let you fix them without angry phone calls. Your colleague will never know that the server had problem, from their point of view, everything works fine even when you took down a server for maintenance.
When your company is small enough(and doesn't need fancy or high availability server), having all server running on 1 host (each without high availability) is still ok, all you need is regular backup(preferably daily and hourly for database). But when the data becomes really important, it's time to think about high availability and disaster recovery. Sadly my boss is still unconvinced, 1 server for each role is enough, having a server with multiple role is good(yes except when the server is running database... like exchange server). Seems like I need God's help to strike the server down and let him know that high availability is God's gift to mortal...
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