Gordon Messmer wrote:
On 06/23/2015 08:10 PM, Marko Vojinovic wrote:
Ok, you made me curious. Just how dramatic can it be? From where I'm sitting, a read/write to a disk takes the amount of time it takes, the hardware has a certain physical speed, regardless of the presence of LVM. What am I missing?
Well, there's best and worst case scenarios. Best case for file-backed VMs is pre-allocated files. It takes up more space, and takes a while to set up initially, but it skips block allocation and probably some fragmentation performance hits later.
Worst case, though, is sparse files. In such a setup, when you write a new file in a guest, the kernel writes the metadata to the journal, then
<MVNCH>
Here's a question: all of the arguments you're giving have to do with VMs. Do you have some for straight-on-the-server, non-VM cases?
mark