Hello, I work for a school in a New Zealand university and we are wanting to implement Server Virtualization for both CentOS and Windows systems. So I thought I would ask here what experience people have had with this and what issues that you all think should be considered? From my own research it seems that VMWare or Xen are really the two major products to be considered, are there any others I should be considering ? Is anyone running Linux "Guest" O/S's inside a Windows host ?? And if so can you share your reasons for this? Anyway thank you for your time and any experiences / knowledge you are willing to share :)
Quoting Clint Dilks <clintd at scms.waikato.ac.nz>:> Hello, > > I work for a school in a New Zealand university and we are wanting to > implement Server Virtualization for both CentOS and Windows systems. > So I thought I would ask here what experience people have had with this > and what issues that you all think should be considered?Xen is great - however you will need Full virtualisation support in your hardware. These are shown as the ?vmx? flag for Intel or ?svm? for AMD CPUs in /proc/cpuinfo. If you are running Windows guest in a linux Xen domain, you will want to pay for the Xen licenses. This gives you access to the windows drivers for disk and network etc - which improves performance immensely.> From my own research it seems that VMWare or Xen are really the two > major products to be considered, are there any others I should be > considering ?I can only really speak for Xen...> Is anyone running Linux "Guest" O/S's inside a Windows host ?? And if > so can you share your reasons for this?I'd say VMWare would be the way to do this - if you really had to.> Anyway thank you for your time and any experiences / knowledge you are > willing to share :)The learning curve for Xen is huge. I would suggest a few things though if you decide to use it. 1) Setup your Dom0 (the host) disk to use LVM. You will want to make MANY partitions. Use a raw disk partition for disk access instead of a file as the disk - performance is much better this way. 2) If you're going to add Windows as a guest OS, make sure you get the Windows drivers. This is something you have to pay for, but the performance increase will be well worth it. 3) use 'xm top' on Dom0 to monitor what your guest systems are doing. Get yourself a multi processor system, and divide up usage between physical CPUs. This way, you get the best usage of your hardware. 4) Get lots and lots of RAM. We use systems with 8Gb RAM. We give the hypervisor 256Mb, and then chunks of 256Mb, 512Mb or 1Gb to each DomU depending on usage. -- Steven Haigh Email: netwiz at crc.id.au Web: http://www.crc.id.au Phone: (03) 9001 6090 - 0412 935 897
On Tue, 2007-09-18 at 11:20 +1200, Clint Dilks wrote:> Hello, > > I work for a school in a New Zealand university and we are wanting to > implement Server Virtualization for both CentOS and Windows systems. So > I thought I would ask here what experience people have had with this and > what issues that you all think should be considered? > > From my own research it seems that VMWare or Xen are really the two > major products to be considered, are there any others I should be > considering ? > > Is anyone running Linux "Guest" O/S's inside a Windows host ?? And if > so can you share your reasons for this? > > Anyway thank you for your time and any experiences / knowledge you are > willing to share :)I use Xen personally and at work I work with VMware. I don't have any machines personally that have hardware virtualization extensions in the processor, so I'm only doing para-virtualization with CentOS 5 as host and guests. Documentation seems a little sparse if you want to deviate from the default configuration too much in Xen. Other than that I've been very happy with Xen. At work we've been playing with VMware Infrastructure 3. If you are going to go the VMware route, this is by far the best bang for your buck. You are able to manage several VM hosts under one interface, and if you are running Windows as a guest you can do some pretty neat things (coming soon for the Linux side). I've also used the free version, VMware Server (also called GSX, Infrastructure comes with the version called ESX) on both Windows and Linux...prefer using Linux though as the host (much better stability and low-level options if you are into customizing the environment). Any more questions, like specifics, please ask. I've been using Xen and VMware for several months now. -- Timothy Selivanow <timothys at easystreet.com> Linux System Administrator EasyStreet Online Services, Inc. http://www.easystreet.com
On Tue, 2007-09-18 at 11:20 +1200, Clint Dilks wrote:> Hello, > > I work for a school in a New Zealand university and we are wanting to > implement Server Virtualization for both CentOS and Windows systems. So > I thought I would ask here what experience people have had with this and > what issues that you all think should be considered? > > From my own research it seems that VMWare or Xen are really the two > major products to be considered, are there any others I should be > considering ?Those are probably the top contenders.> Is anyone running Linux "Guest" O/S's inside a Windows host ?? And if > so can you share your reasons for this?No. If there are reasons, they are beyond my understanding. :-)> Anyway thank you for your time and any experiences / knowledge you are > willing to share :)I use VMware Server & Workstation - primarily for testing new Linux releases and for running Windows apps under Linux. Have run some services for testing purposes and find performance and functionality to be pretty good. You may want to join the new CentOS Virtualization list to find a more targeted audience: http://lists.centos.org/mailman/listinfo/centos-virt Phil
Clint Dilks wrote:> > Hello, > > I work for a school in a New Zealand university and we are wanting to > implement Server Virtualization for both CentOS and Windows > systems. So > I thought I would ask here what experience people have had > with this and > what issues that you all think should be considered?Irrespective of which virtual server solution you choose be aware that virtualization brings with it steep storage requirements. Think of providing around 1TB of RAID10 storage for 20 guests. VMs do lots of tiny random IOs so for 20 guests split between 2 servers I provide 500GB of RAID10 to each via iSCSI SAN.> From my own research it seems that VMWare or Xen are really the two > major products to be considered, are there any others I should be > considering ?Not really.> Is anyone running Linux "Guest" O/S's inside a Windows host > ?? And if > so can you share your reasons for this?I do at work so I can prototype some Linux stuff on my Windows box.> Anyway thank you for your time and any experiences / > knowledge you are > willing to share :)I would try both VMware server and Xen on CentOS, if you have 2 servers set them up side by side and plugged into your storage SAN. Run them through their paces, do some benchmarks get a feel for ease of use and maintenance. When your ready and have a budget you can move up to the commercial versions, ESX and Xen Enterprise. -Ross ______________________________________________________________________ This e-mail, and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail, you are hereby notified that any dissemination, distribution or copying of this e-mail, and any attachments thereto, is strictly prohibited. If you have received this e-mail in error, please immediately notify the sender and permanently delete the original and any copy or printout thereof.
> I work for a school in a New Zealand university and we are > wanting to implement Server Virtualization for both CentOS > and Windows systems.Keep in mind virtualization software is moving pretty quickly. 8 months ago Xen didn't migrate fully virtual hosts, now it does. In 5 years the rediculous pricing structure for Virtualization technology will be gone and virtulization will be a commodity where all you pay for are accelorating drivers and managment tools. If you check the virtualization page on wikipedia http://en.wikipedia.org/wiki/Virtualization#Virtualization_examples you'll see a bunch of the questions you should ask to figure out your reasons for going virtual. Try to rank the features you know will help you frequently, and the stuff that's just "WOW! Moving a running server is so cool!". Try to avoid cool stuff for cool stuffs sake. Live host migrations are great if you have dynamic workloads or for the occasion you need to take a physical machine down for firmware/hardware updates during buisness hours, but think of how often you are going to use it and what impact downtimes might have.> From my own research it seems that VMWare or Xen are really > the two major products to be considered, are there any others > I should be considering ?Take a peak at KVM (http://kvm.qumranet.com/kvmwiki/Guest_Support_Status). Might not be ready for primetime, but it is pretty favored by the kernel maintainers for simplicty and cleanliness so it's likely to end up going further than Xen. Do you really think the hypervisors and managment software isn't going to endup in hardware? If it's "Enterprise Level Support" and performance you pretty much have to go with VMware. Realistically, for most companies and workloads way to many things are tagged as "Requiring Enterprise Class", and you can get away with Xen and KVM. The free VMWare Server (aka GSX) is a completely different beast from VMWare ESX, performs pretty terribly, and is almost worthless for production servers. ESX is amazing, and I'd recommend it if you have the money, but I it's like 3K every 2 sockets and needs a san to be very useful. You can quickly rack up 50 grand in hardware and licensing just to get off the ground. If I had the time, I'd like to try using Xen with an OpenSolaris ZFS iSCSI target as shared storage, but alas I do not have that time.> Is anyone running Linux "Guest" O/S's inside a Windows host > ?? And if so can you share your reasons for this?I've done for people I work with because cygwin is too much of a moving target, or to test that their code compiles and works on both platforms. I also sniffed alot of glue when I was younger. Patrick