Trying out Xen
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@DustinB3403 said:
XenServer has a Live CD that you can install directly to a dedicated drive. Which builds Dom0, Dom0 the resides on that disk as an 8GB partition.
Right, but XenServer installs CentOS 6. You aren't saving anything. It's no different than installing Xen with OpenSuse or Ubuntu, just easier because XenServer packages CentOS and Xen up together for you to do the install all at once. You still have the same OS overhead as any other Xen installation method.
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We got it from : http://xenserver.org/overview-xenserver-open-source-virtualization/download.html and installed directly to a dedicated drive that we threw into out VM Host
We specifically didn't want to use a Thumb drive to run the Distro.
But thinking about it afterwards it would probably be easier to make a clone of a Thumb Drive ISO for backup purposes.
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I'm not saying that XenServer isn't a good idea, it is what I usually recommend because it is fully packaged and tuned for exactly that one purpose and everything is set up for you right out of the gate. It is almost a no brainer. But very important to understand what it is doing and that it is not lighter or anything.
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@DustinB3403 said:
We specifically didn't want to use a Thumb drive to run the Distro.
But thinking about it afterwards it would probably be easier to make a clone of a Thumb Drive ISO for backup purposes.
Yes, thumb drive is "always" better. That's just good practice for a hypervisor. No benefits to using a hard drive. The only reason that XenServer is often put on spinning rust is because it does not have a native "install to thumb drive" option and takes some extra effort, unlike ESXi which takes literally zero effort to have do that.
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"Spinning rust"
Gonna have to remember that one
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And we didn't want to install Ubuntu Server or some other distro and install Xen into that because of the previously mentioned setup.
That would be extra overhead.
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@DustinB3403 said:
"Spinning rust"
Gonna have to remember that one
That's a pretty standard term, actually, for traditional spinning hard drives. One of the few terms that isn't easily confused with other types of drives
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@DustinB3403 said:
And we didn't want to install Ubuntu Server or some other distro and install Xen into that because of the previously mentioned setup.
That would be extra overhead.
Not really. You have to understand how Xen works. In every instance it needs a Dom0. In XenServer the Dom0 is a full version of CentOS 6.
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@DustinB3403 said:
And we didn't want to install Ubuntu Server or some other distro and install Xen into that because of the previously mentioned setup.
That would be extra overhead.
That's what I don't understand. What extra overhead? Where is the extra overhead coming from? I think there is some confusion as to how Xen works because this statement doesn't make sense.
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If we setup our Hypervisor with a baseline Ubuntu Server Distro, and then apt-get Xen, the Ubuntu server would then be overhead.
The installer it's self creates the required VM to run the hypervisor.
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@DustinB3403 said:
If we setup our Hypervisor with a baseline Ubuntu Server Distro, and then apt-get Xen, the Ubuntu server would then be overhead.
The installer it's self creates the required VM to run the hypervisor.
But that isn't really anymore overhead then the CentOS 6 installation that XenServer includes.
Don't get me wrong, I recommend XenServer quite often (even use it for my home lab) but it really is no different then installing Xen on top of Ubuntu. Aside from having some additional pre-built tools.
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@DustinB3403 said:
If we setup our Hypervisor with a baseline Ubuntu Server Distro, and then apt-get Xen, the Ubuntu server would then be overhead.
No, there is no overhead. Where are you thinking the extra overhead is coming from?
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Wouldn't that Ubuntu distro take away from your baremetal resources though in comparison to just letting the Xen installer do its thing?
oh and Scott at my home lab I setup Xen to a 16GB flash without any issues at all, it was very, very easy to do.
Like with any other linux distro it's built in with version 6.5
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@DustinB3403 said:
The installer it's self creates the required VM to run the hypervisor.
No, that's not a good description. It converts the running Ubuntu instance into the Dom0. Exactly how HyperV works as well.
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Maybe this will help.
XenServer install = Live CD installing CentOS 6 AND Xen
Traditional Xen install = Install your preferred version of Linux, then install Xen into that.
Both must have a base Linux install called Dom0
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@DustinB3403 said:
Wouldn't that Ubuntu distro take away from your baremetal resources though in comparison to just letting the Xen installer do its thing?
How? Xen is a bare metal OS. The Ubuntu is the Dom0 that you can't avoid no matter how you install. Xen controls all of the resources. Yes the Dom0 uses a small amount of them, but always the same amount where you install this way or install from CentOS 6 like XenServer does.
XenServer installs identically, it just doesn't show you the process as it is all automated.
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@DustinB3403 said:
oh and Scott at my home lab I setup Xen to a 16GB flash without any issues at all, it was very, very easy to do.
I know that @Mike-Ralston was working on that a bit and was having issues with the install. Maybe he didn't try between 6.2 and 6.5.
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I never though of using Ubuntu as Dom0 all of the documentation I read when getting everything setup recommended letting the installer create Dom0 for you.
Isn't that best practice, rather than installing your own Dom0?
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@scottalanmiller said:
No, that's not a good description. It converts the running Ubuntu instance into the Dom0. Exactly how HyperV works as well.
I thought the standalone HyperV didn't have a Dom0 OS - that it was exactly like ESXi, just a smallish Baremetal install.
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@Dashrender said:
I thought the standalone HyperV didn't have a Dom0 OS - that it was exactly like ESXi, just a smallish Baremetal install.
Nope, nothing would work that way for two reasons:
- You would never offer the penalty of a Dom0 if you didn't need it. That would be crazy. Getting to VMware's approach is the holy grail of hypervisor design.
- You would never engineer a product in two ways like that, it would cost a fortune.
