What's the best way to requisition a VM for a networking device?

[deanwebb]

If I need to have virtual resources for a network device that is critical for operating the network, such as a NAC or SDN controller, what are the key words I need to use in order to make sure that I get dedicated resources on a VM host that's not about to crater due to too much stuff running on it? And what are the terms to use to describe the kind of VM host that I DO NOT want to have for my critical network virtual devices?

I've got some ideas from discussions with my VM team, but I don't know enough about the VM environment to know if I've asked all the relevant questions.

[icecream-guy]

You need RAM, Disk space, and CPU requirements....

[deanwebb]

Got those. But what's the real difference between thick and thin provisioning? How bugged out about oversubscription should I be? What if they never clean up backup snapshots? What else can poleaxe a VM host that I don't yet know about, given that I know next to nothing about VM hosts?

[Fred]

The keyword is a reservation.  Most vendors will insist that you need reservations for 100% of the resources that the machine is allocated.  You basically have to do this in order to get support.

IMO, it's crazy and unnecessary.  VMWare does a damn good job of sharing resources and keeping the resource hog in check.  IMO, if your VMWare team is competent, you can let them take a little bit of leniency toward the reservations. It's their job to make sure that your machine is getting what it needs.

You may want to ask them how they handle snapshots.  Snapshots can kill performance, so any vmware team worth their salt has a process in place to monitor and remove outdated snapshots.  If they're using them for more than brief fallback plans, they're killing performance.

[deanwebb]

You are very right on snapshots... very very right...