Xen and Mdadm?
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@DustinB3403 said:
@scottalanmiller So to summarize what you've said,
If it's a software appliance that you need support on (and you aren't changing the code) get general IT support as it's often far better of a fit for support because the general IT support company understand what the business (customer) is trying / doing.
Correct?
Yes. And I'll provide an example...
You get a NAS, let's just say a Synology. Synology will support it (it's even free and included.) But their support extends only to making sure that the Synology itself is working properly - which it should be doing anyway. They know their own product well, but there isn't very much to know. They can't tell you what protocol is best for you to use, how to hook it up. which drives to buy, what RAID level to choose, what IP addressing scheme to pick, if it should be on the LAN or SAN, what network aggregation system to set up, what MTU size to set, can't work with the devices that connect to the device and on and on.
The one support is very, very isolated. The other is inclusive.
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Wow I got a crash course in the finer naming art of Xen. Very cool. BTW, I should have kept my same username name from Spiceworks when I joined here. I recognize both Dustin and SAM from over there.
I'll check out that tut you linked to Dustin. Would I be correct in saying that while Mdadm works just fine it isn't really "supported" in this configuration with Xen? In other words, is this not something you would do on a production machine?
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@biggen said:
Would I be correct in saying that while Mdadm works just fine it isn't really "supported" in this configuration with Xen?
This is where those names get really important.
Xen itself doesn't support or not support anything. It doesn't have the concept of "support" when used in that way.
XenServer does have an "official HCL and supported setups" according to Citrix - who doesn't make the product and that's just a list of ways that they support the use of XenServer.
XenServer itself ships with MD RAID (another naming thing, MD is the RAID, MDADM is the tool to configure it) and it is built in so 100% supported by XenServer itself and every enterprise product to ever ship with Xen has MD RAID support built in.
Xen is available with OEM support from Red Hat, Oracle, Suse, Canonical (Ubuntu) and others - every one of them supports MD RAID.
So MD is very, very much supported. Citrix is alone is not recommending it or officially calling it supported.
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@biggen said:
In other words, is this not something you would do on a production machine?
I would absolutely use it in production. MD RAID is an enterprise ready product with decades of experience in the most demanding environments.
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My only warning is that MD RAID is a bit more "enterprise" than hardware RAID with blind swap so in the SMB market I normally advise that people use hardware RAID because SMBs tend to lack the storage understanding and support infrastructures for software RAID. It's not that software RAID isn't as good or possibly better, it is that SMBs often have false expectations and understandings and hardware RAID caters to that.
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Thanks Scott that is very helpful. I've enjoyed playing around with MD on my Ubuntu Server. Learned a ton. I think moving it to a VM via XenServer sounds like another good learning expierence.
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@scottalanmiller said:
You can do the simplest thing and just buy blocks of hours to use. Then you can use them for whatever you want.
What size are the blocks packaged?
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@FATeknollogee said:
@scottalanmiller said:
You can do the simplest thing and just buy blocks of hours to use. Then you can use them for whatever you want.
What size are the blocks packaged?
All different. A conversation with @Minion-Queen @ataylor14 or @jenuinecase would be best as they could provide real details. But you can buy single hours, but the bigger the blocks the bigger the discounts. I know lots of places buy then at ten hours at a time or a hundred hours at a time.
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Just so I'm clear on that link that Dustin provided (but looks like Scott wrote), I can install XenServer on a USB stick, put my VM's on a RAID 1 SSD datastore and my actual media for my NAS on a separate RAID 1 winchester?
Mdadm can manage both arrays like this?
I know that guide was for RAID 10 but I can adjust it pretty easily for twin RAID 1 arrays.
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Not being familiar with XenServer the last command "xe sr-create" is new to me.
Once XenServer is installed and I create my desired MD RAID devices via the CLI, can I not use a GUI to add them to XenServer as datastores?
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@biggen said:
Just so I'm clear on that link that Dustin provided (but looks like Scott wrote), I can install XenServer on a USB stick, put my VM's on a RAID 1 SSD datastore and my actual media for my NAS on a separate RAID 1 winchester?
Mdadm can manage both arrays like this?
I know that guide was for RAID 10 but I can adjust it pretty easily for twin RAID 1 arrays.
Dustin wrote most of it. I polished it and posted it for him.
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@biggen said:
Not being familiar with XenServer the last command "xe sr-create" is new to me.
Once XenServer is installed and I create my desired MD RAID devices via the CLI, can I not use a GUI to add them to XenServer as datastores?
When you are creating the datastores they will automatically be added within XenCenter.
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@DustinB3403 said:
@biggen said:
Not being familiar with XenServer the last command "xe sr-create" is new to me.
Once XenServer is installed and I create my desired MD RAID devices via the CLI, can I not use a GUI to add them to XenServer as datastores?
When you are creating the datastores they will automatically be added within XenCenter.
But that's only after you add them as datastores in XS, right?
I think the answer to biggen's question is no, you can't add raw storage to XS as a datastore through a GUI unless XO supports that. XenCenter does not support this.
it's not as clean/single interface for everything GUI-wise like ESXi is.
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Yes you have to create a Storage Repository (SR) first with the "xe sr-create <details>" command which automatically adds it into XenCenter (visually) and Xen on the back end.
Otherwise it would be like putting a hard drive into a system and telling the system to do nothing with it.
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@DustinB3403 said:
Yes you have to create a Storage Repository (SR) first with the "xe sr-create <details>" command which automatically adds it into XenCenter (visually) and Xen on the back end.
Otherwise it would be like putting a hard drive into a system and telling the system to do nothing with it.
@biggen said:
Not being familiar with XenServer the last command "xe sr-create" is new to me.
Once XenServer is installed and I create my desired MD RAID devices via the CLI, can I not use a GUI to add them to XenServer as datastores?
So he specifically asked if he can use a GUI to add them. You can in ESXi and Hyper-V, but apparently no, you can not use the GUI to do this in XS.
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Well you could run the commands from XenCenter using the Console of the Xen installation to do this.
But it's not a "point and click" function
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@Dashrender said:
So he specifically asked if he can use a GUI to add them. You can in ESXi and Hyper-V, but apparently no, you can not use the GUI to do this in XS.
Not quite fair as VMware can't do this at all. So you can't do it from there at all, CLI or GUI.
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Xen... XenServer... Xen server... Something I haven't looked into is the pricing. Xen is open source & free at the same time, that I have gathered. XenServer is something that Citrix has created, and charges for (open source, but not free... Red Hat in the same fashion. Open source, but not free). Xen server, any Xen server (can be open source and free, or can be XenServer... It's just a vague term). Anyone have any input? I'm always looking at new options for cost effective deployment in the right environment.
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@BBigford said:
Xen... XenServer... Xen server... Something I haven't looked into is the pricing. Xen is open source & free at the same time, that I have gathered. XenServer is something that Citrix has created, and charges for (open source, but not free... Red Hat in the same fashion. Open source, but not free). Xen server, any Xen server (can be open source and free, or can be XenServer... It's just a vague term). Anyone have any input?
XenServer is open source and free. Just like Redhat if you want to pay for support you can. Even with XenServer you get all the updates for free. XenServer was "created" by Citrix, but they have since GPL'd (I think) the code and have given the code base to the Linux foundation. There is no obligation to pay for it.
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@BBigford said:
Xen... XenServer... Xen server... Something I haven't looked into is the pricing. Xen is open source & free at the same time, that I have gathered. XenServer is something that Citrix has created, and charges for (open source, but not free... Red Hat in the same fashion. Open source, but not free). Xen server, any Xen server (can be open source and free, or can be XenServer... It's just a vague term). Anyone have any input? I'm always looking at new options for cost effective deployment in the right environment.
It's all open and all free. XenServer has no way to not be free because the license protects you. Citrix didn't create XenServer, it's built from Linux' Xen project and CentOS. Citrix just bundled it and sold support. And even that is in the past. Xen, XenServer are both part of the Linux Foundation, are both GPL and that means free.
