Adding CPU to existing VM

[howartp]

Hi.

 

Our SIMS server is 20GB RAM with SQL locked to 14GB, but SQL is using all the CPU (which is 2x2 vCPUs).

 

Googling adding CPU gives hundreds of articles about the merits/cautions of hot-add, but i've no intention of hot-adding - what I want to know is, does Windows Server 2016 support adding more CPUs when the VM is shut down?

 

In the olden days, changing cpu or motherboard would kill Windows on a physical PC unless you got drivers and chipsets all sorted properly beforehand - is this still the same with Windows Server 2016 on vSphere 6.7?

 

Peter

[aicrd]

I add and remove vCPUs from VMs all the time, even on Server 2008 with no issue at all. On both ESXi and HyperV. If you are only changing the amount of vCPUs i don't see any issue.

[3s-gtech]

Did it recently on a Hyper-V VM - I’ll need to do it on ESXi shortly too. Not had any issues - the last time I saw a problem was when going from a single core Athlon 64 to dual core Athlon X2 on Windows XP (so quite a while back!)

[Jcx500]

Been adding and removing vcpus for ages now , just upped an apps server from 2 vcpus to 4 and it’s working great

[howartp]

Thanks everyone.

 

Not something i've ever tried before but it looks to be ok on the test VM (ie my technician's!) so i've just done SIMS.

 

I'm isolating for the week now so I can leave it to my colleagues to fix if it breaks!

[Katy]

In the olden days you got a different version of the kernel installed it it was single CPU rather than multi CPU, so back then - you could increase if you already had more than 1. These days it doesn't make any difference, if Windows needs to do anything differently it handles it all for you.

[Roberto]

In the olden days you got a different version of the kernel installed it it was single CPU rather than multi CPU, so back then - you could increase if you already had more than 1.

 

I remember that. I came up with a (relatively) safe method of moving from the single processor to multiprocessor kernel for NT4 that pretty much got me my first MVP award by itself when I shared it.