On Tue, Jun 26, 2012 at 9:05 AM, Nicolas Ross rossnick-lists@cybercat.ca wrote:
I have some general questions about VM.
If I set vcpu let's say to 2-3 for a single vm, does this mean that those CPU are dedicated to that vm or many vm can share the same physicial cpus ?
No, all the CPU will be virtualized and shared. Although there is "affinity" option where physical CPU is locked to a certain VM. But in general this option gives more bad effect than good.
So, I was wondering what's the best for managing storage for VMs ? I see mostly recomandations for LV for storing VM's disks. It seem to helps to create snapshots for backup purposes. Is this the fastest way of creating backups ? And will data access be faster that if I use regular files ?
Using LV will give you flexibility among other things. Better have it in the beginning rather than sorry later (e.g. running out of space, etc). The performance difference is insignificant.
In my case, the "main" setup of each vm is rather simple. The minimal OS, updates, my own httpd, my own php a couple of other packages. So restoring a VM from scratch can take less than an hour. So I was thinking of not taking snapshot of the whole VM and only sync the data partition.
That's ok.
As for the guest paritions, I am accustomed of separating my servers disks with separate /, /usr, /var, /home and /data partitions. I can't recall today why I started doing this, 15 years ago, but I still like it that way and continue to do so. Do I still "need" to do this with VMs ?
The reason of creating separate partitions is mainly for security and preserve data during reinstallation. I believe it's still good to do your way.