kvm driver

[jcaleb]

hello admin/uncle,

which network and disk driver are best to choose for each case of linux or freebsd?

thanks

[Admin]

I suspect KVM since bsd doesnt really run on others.
In case of KVM VirtIO is a must, unless you have tons of cpu, because using ide and even scsi will put a large strain on the cpu.
Freebsd will probably have virtio support, linux has already.
If you dont have big transfer on network, any will do, but also virtio is recommended.
This is the XEN-PV approach, they modified kernel of guest to push io to the host kernel, Rehat is doing something similar, tho not so high in the kernel space.
I must admit Redhat did a better design here, however, Xen-PV is still faster and will always be.
M

[jcaleb]

Thanks admin.

Sorry I forgot to mention I was only referring to KVM. So regardless if I use linux or BSD, I should always use virt driver for both network and disk drivers right? Thanks!

[Admin]

I imagined you mean KVM since bsd doesnt run on something else (except xen HVM).
You can do without, but performance will suffer.
The more iops and network traffic you will have, the more cpu will you lose.
KVM can only compete in speed somewhat with other techniques due to the VirtIO drivers.
Admin

[jcaleb]

Thanks. Admin, you are M? I thought you were John

[jcaleb]

Hello,

One of my KVM is using Intel Pro /1000 Network card. Do I need to set it to virtio and reinstall? Or would this just run fine?

Thanks

[Admin]

In general, VirtIO is preferred. If you have big traffic of small packets, your CPU will breathe easier, if you are OK with CPU performance and reinstalling will be a big hassle, it is not really necessary, just a recommendation.
One question though, why do you need to reinstall ? Just changing the emulation should make the OS autodetect it and work like that in most recent linux cases.
Which OS are you using ?
Admin

[jcaleb]

Thanks for the explanation. I am using Debian 6. I didn't know it would work without reinstalling.

[Admin]

You can switch back if it doesn't work. But I doubt, it shoud

Admin