Oliver Fischer wrote:
Hello Vishal,
I did the same some weeks ago. The most important fact is, that it
works. But it is horrible slow if you not have enough ram and multiple
disks since all I/o-Operations go to the same disk.
they may go to separate disks underneath, but performance is bad as what
the virtual OS thinks is a raw hard disk could be a badly fragmented bit
of storage on the container OS.
Memory is another point of conflict; your VMs will swap out or block
other vms.
0. Keep different VM virtual disks on different physical disks. Fast
disks at that.
1. pre-allocate your virtual disks
2. defragment at both the VM and host OS levels.
3. Crank back the schedulers so that the VMs aren't competing too much
for CPU time. One core for the host OS, one for each VM.
4. You can keep an eye on performance by looking at the clocks of the
various machines: if they pause and get jittery then they are being
swapped out.
Using multiple VMs on a single host is OK for testing, but not for hard
work. You can use VM images to do work, but you need to have enough
physical cores and RAM to match that of the VMs.
-steve
