Maximum number of virtual machines

Question

Virtualization

Good day, friends.

There is an application (LAMP) that they want to sell as SAS. But in view of the specifics of the application (rather deep access to the server FS), there is an idea to run each application instance in a virtual container.

Hence the question:
- how many maximum virtual machines can be untwisted on 1 piece of iron?
- what other methods of "virtualization" of FS are there?

Answer 1

Depends on the selected virtualization tool and workload.
Write more.
The same LXC easily holds 20-30 machines (of course, if the load does not exceed that which dom0 could withstand).

Answer 2

Good afternoon.
No one will tell you the maximum of virtual machines just offhand, because there is not enough input data, in theory, as much as processors and virtual memory will allow. Disk space is somewhat easier, you can use network storage.
One of the methods of "virtualization" of FS is the use of deduplication, which is possible, for example, when using ZFS. It is used in hardware storage systems, from software solutions - FreeBSD or Nexenta. During deduplication, matching data blocks will not be duplicated, links to blocks with the same content will be used, which will save disk space.
With RAM, a similar mechanism is used, for example, in VMWare products, where, as far as I know, memory pages are deduplicated during operation, which allows you to actually run virtual machines that consume more resources than there are on a physical machine with a hypervisor. However, similar mechanisms are now available in other hypervisors, for example, Hyper-V.
If deep work with the file system is required, then one of the options is to use ZFS storage + iSCSI as block devices for virtual machines.

Answer 3

What is the load on virtual machines? What hardware is planned for the host machine? What hypervisor? Everything is individual here.

Answer 4

> OR how to virtualize the Filesystem + LAPM infrastructure into a separate chroot.
On FreeBSD, for example, there is a "jail" - in this case, individual FreeBSDs are chrooted and resources are not spent on virtualization.

Answer 5

How many copies of the application you can run the same number of virtual machines on some kind of openvz you can do, the overhead is very small there.