Re: Slow reboots windows 2008 x64 4VCPU and 8gigs ...

jslarouche · ‎04-28-2009

We are also experiencing the slow reboot times on three different clusters.. Not sure what overall impact this does if we did the workaround.. Does anyone know?

KB Article

1004901

Has anyone implemented this change and has seen no other impacts on memory performance?

Troy_Clavell · ‎04-28-2009

try reducing your vCPU count to maybe 1 or 2 to see if that fixes it.

BarryCoombs · ‎04-28-2009

What is the VM used for? Has analysis of the performance figures been carried out? Have you spec'd the virtual machine according to this? In most enviorments you will fine 1vCPU is enough and 2 in worst case scenarios. It would be very rare that 4 would be required.

What is the current memory usage on your host, are you currently over commiting memory at all?

Can't say I have experienced any slow reboots with the VM's at our site or our customers for anything other than software delays.

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azn2kew · ‎04-28-2009

What kind of applications are you running for this 4 vCPU guest? It seems like you are overallocated unncessary virtual CPUs for that VMs, in theories, if you understand resource management from ESX, you wouldn't want to use 4 vCPU unless it really uses it all but most of the time it will create a performance bottleneck. As recommended, change it to 2 vCPU if its Exchange, Oracle, SQL boxes. You should check out resource management guide for details

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jslarouche · ‎04-29-2009

These servers are currently being built for Exchange 2007 backend servers. So they require this type of resources..

wila · ‎04-29-2009

Hi,

Did you set memory reservations on those VMs? If so how much?

If you do not set a memory reservation, then during boot time, the hypervisor will create a swap file as big as the memory that the VM has, so for an 8GB VM, it will create a 8GB swap file on disk and this might take a little while.

By setting a reservation, the size of the reservation is removed from the size of the vmkernel swap file.

So for example by setting a 5GB memory reservation, only a 3GB swap file is being created.

All

Slow reboots windows 2008 x64 4VCPU and 8gigs of RAM.