New on LowEndTalk? Please Register and read our Community Rules.
All new Registrations are manually reviewed and approved, so a short delay after registration may occur before your account becomes active.
All new Registrations are manually reviewed and approved, so a short delay after registration may occur before your account becomes active.
Comments
Ballooning is still quite different to overcommitting RAM in OpenVZ. 8x overselling of resources & hurting the guest VMs so badly is possible with OpenVZ only.Like @W1V_Lee said overselling is fine if it doesn't affect individual client performance but unfortunately the vast majority of hosts don't care.
Oh noes, vmware is made for overselling as well! https://labs.vmware.com/vmtj/memory-overcommitment-in-the-esx-server
I'd like KVM & openvz
Do you mind explaining how a 8x overprovisioned ballooned xen server is different than the openvz? For sake of illustration, let's say that initial baseline usage per user happens to be 1/8 of sold capacity. Then ramp their usage up to full.
You're absolutely right. Someone needs to tell the good people at Paralles that in 2014 hardware has become affordable and abundant enough that overselling is not a good business practice anymore in web hosting, unless of course you want a container 4GB or more RAM on paper for bragging rights for dirt cheap. The ability to properly take advantage of your resources as a customer, well, that's an entirely different story.
I host some gameservers too (CS, Minecraft, AoS and some other games) and had never problems with my servers. Everything was perfect. I think you just have to use the right hoster, which doesn't oversell their node(s).
I meant different in the sense that end customer can easily know if Ballooning is in effect using a simple command which is not possible in OpenVZ. But I would like some reputable providers like @AnthonySmith @Maounique @Nick_A to shed light on topic of overselling that if it is practically possible in ahosting environment to overallocate memory in XEN or KVM in same way as OpenVZ
OVZ is made to be scalable on the spot, because it is not really a virtualization, but some sort of very much evolved shell or jail. Processes in OVZ are isolated, but resources are not and can pass from one process to the other and disk space is allocated with quota.
The other types have various particularities, but are emulating more or less a separate machine with own memory, NICs, CPU, bus, partitions. You can use thin provisioning to under-allocate disk, however, once expanded, it cannot be shrunk easily, also you can deduplicate memory and use various techniques to overprovision it, but most of them can be stopped from the inside if the user is not "cooperating".
VMWare is probably the easiest to oversell of all (except containers, of course).
Out of all, the best compromise seems to be Xen-PV, it has a very low overhead and is more or less a complete emulation suitable for most usage scenarios in a VPS all others (windows, other unixes-though you can run BSD-like, for example if you really wish to- as well as ISO installs, etc) are either coming up in 4.4 or can be achieved using the HVM version.
Conclusion: All can be oversold, but it is not worth it bothering with others, except VMWare, maybe. Apart from containers, of course.
Disclaimer: I said nothing about overselling IOPS and CPU and network, that can be done in all versions, the best compromise seems to be aslo Xen-PV with great cpu sharing and good IO priority management.
It is one of the features and if you read that page the reason if not removing it despite cheaper hardware these days is:
"With a continuing fall in the cost of physical memory, it can be argued that ESX does not need to support memory overcommitment. However, in addition to traditional use cases of improving the consolidation ratio, memory overcommitment can also be used in times of disaster recovery, high availability (HA), and distributed power management (DPM) to provide good performance. This technology will provide ESX with a leading edge over contemporary hypervisors."
VMware is also a bare metal virtualization instead of containerization. In my personal opinion Vmware performs as good as KVM/XEN.
The only place of their website where I found this feature but not as highlighted on Parallels website is the free hypervisor page which is not meant to be used by vps providers/resellers.
http://www.vmware.com/ap/products/vsphere-hypervisor/
When a vitualization technique CAN overprovision easily with minimal cost some resources, it is criminal not to. Overprovisioning saves power, materials, transportation, man-hours, etc if done right, which also means it drives prices down.
"Overselling" is a very good thing the bad name it is given by a few people which do not know how to do it and/or take into account peaks and all. It is spending a bit of thinking to save a lot in materials, power and costs.
Absolutely correct
I think the whole Ram issue is really irrelevant anyway, I mean if overselling of ram was an issue causing problems for people this is exactly the forum you would hear about it and well frankly we are not.
Regardless of which virtualization you choose it will have little difference from a security/performance point of view if the person managing it has a low cell capacity upstairs. And let's be honest, there are plenty of those around here and more frequently now on WHT.
Pick the provider carefully before you worry about choice of virtualization.