On 6/24/2015 1:06 PM, m.roth@5-cent.us wrote:
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
Is there an easy to follow "howto" for normal LVM administration tasks. I get tired of googling every-time I have to do something I don't remember how to do regarding LVM, so I usually just don't bother with it at all.
I believe it has some benefit for my use cases, but I've been reticent to use it, since the last time I got LVM problems, I lost everything on the volume, and had to restore from backups anyway. I suspect I shot myself in the foot, but I still don't know for sure.
thanks, -chuck