Trying to migrate



  • Hi,
    I'm trying to migrate between to hosts with XO. I pick the other host and its storage. Then the migrate process is starting, regarding to the "tasks menu". But when finished the VM hast moved. I got one yellow ! when choosing the storage (local hdds) on that hosts I'm migrate to, which says: "Default SR not connected to host" but it is I can use it.
    But, here is the problem, I think, if I make the storage on the hosts I'm trying to migrate to, to default SR then it is working. But I guess I shouldn't be force to change that everytime I need to migrate a VM 😃
    I'm using a pool with 2 hosta and with no HA enabled.


  • XCP-ng Center Team

    @fraggan did you select a default SR (on each server/pool)?

    Here the SR view of a pool in XenOrchestra and the button to set a default SR:
    d0f47753-21ad-4902-b422-3feeac9626da-grafik.png



  • @borzel
    Yes I did that. And then I worked one way A->B. But then the "default SR" moved to B. But when I wanted to go B->A I had to do the same thing again. I couldn't get both local storage to be "default SR". I just moved the tag along 😄

    Edit: I just want to migrate between 2 hosts with local storage.


  • XCP-ng Center Team

    @fraggan ahhh!!! So you have ONE pool with TWO hosts, but each host has it's own local storage?

    If yes, thats your problem. Pools are just usefull if you have shared storage (like NFS)



  • @borzel said in Trying to migrate:

    @fraggan ahhh!!! So you have ONE pool with TWO hosts, but each host has it's own local storage?

    If yes, thats your problem. Pools are just usefull if you have shared storage (like NFS)

    Most people IMO would expect this. Individual host in a single pool so a VM can be moved within the pool if any given host goes down.


  • XCP-ng Center Team

    @DustinB What you describe is possible without a pool. No need for that.



  • @borzel said in Trying to migrate:

    @DustinB What you describe is possible without a pool. No need for that.

    This I understand, the issue comes in that everything within XO pushes the end administrator to setup a pool with their hosts (even when they don't have shared storage).

    The key is automatically migrating those VMs (which I don't know would work without a pool.)


  • Admin

    everything within XO pushes the end administrator to setup a pool

    What?

    The key is automatically migrating those VMs

    What?



  • @borzel
    Sorry for late reply much at work now before vacation 🙂 Yes thats the situation. For me, creating a pool, would seem to be the obvious thing to do when having more than 1 host 🙂 Since VM can share resources. So...how can I manage this? My plan was to hook them up with a melanox 10 GB NIC and use that for "internal traffic" such as migrating etc. If this isn't possible in current setup I would be happy if you could mention that why creating a pool without single storage, or when trying to migrate them. This HA function should be able even if there are 2 different local storage.

    I might have the change to get my hands on a san but... 😃 Then I have even 1 more machine 😄


  • XCP-ng Center Team

    @fraggan said in Trying to migrate:

    his HA function should be able even if there are 2 different local storage

    • no, there is no (classical XenServer) HA at all with local storage
    • Live migration is always possible: with pool, with sepparate hosts, with local storage, with shared storage... everytime!
      • XCP-ng Center can do it
      • XenOrchestra can do it
      • YOU can do it (if your mindset is in the right mood 😉 )

    Since VM can share resources.

    • VM's do not share resources in a pool unless you have shared storage AND the next point is fullfilled
    • VM's do share disk space if they are on the same storage AND have the same base image (via snapshots/templates and thin coping them at creation time) - THIS IS NOT A POOL FUNCTION

    So, to recap: I you have no shared storage, creating a pool is wasting your time!
    (unless you want to group a LARGE amount of servers - only for administration purposes - not for function)



  • @borzel
    Well the problem is: I cant migrate so, without having to change the default storage everytime very inconvinient =). Do I need to remove the pool to make it work then? DToes XO understand that there are 2 different local Default storage? There are some futures/function I like to with pools. But if thats the problem I can live without them. I only want to be able to move them however I like.


  • XCP-ng Center Team

    @fraggan said in Trying to migrate:

    DToes XO understand that there are 2 different local Default storage?

    YES! Of course! As I sad, you don't need a pool.


  • XCP-ng Center Team

    @fraggan to proove that, here a screenshot of the storages in XO at work:

    bfd15bd0-330d-45f3-ae46-e095a7d60f3b-grafik.png



  • @borzel
    I created the pool for other reasons. But why cant I do like you do? I've tried that like 10 times. But everytime I chose one as default the tag moves away from the other one. Both my hosts local storage cant be default at the same time. Thus I'm not able to migrate between them.



  • @borzel
    I am not at home now. But do you have any suggestions? If the pool doesnt interfere I will keep that. But I am keen to solve the problem 😃 I need to move them around now and then.
    Btw how do I earn reputation? Annoying not to be able to post when I want, have to wait 120 sec 😃
    Edit: In my world that shouldn't be any problem to have two default storage on two different hosts.


  • XCP-ng Center Team

    @fraggan

    I created the pool for other reasons

    which?


    ONE pool can just have ONE default SR

    You have ONE pool, so you can just choose ONE SR to be your default SR. To resolve it, migrate all your VMs to ONE host and remove the other host from that pool, so you have now TWO separate HOSTs.

    Now you can set the default SR on each host, like I did at work.



  • @borzel
    Perfect the answer I was waiting for 😃


  • XCP-ng Center Team

    @fraggan that is the same as we all said earlier in this thread 🤔 at least, we all thought it was obvious ...

    Please share to us: what are the reasons you created a pool?



  • @borzel
    I want to be able to manage everything and share resources. Every benefith you get by creating pools. Hmm...I want everything in XO for ez mangement. Hmm now I am a bit confused. I want to manage every host I have trough XO. But I want all to have their own default storage. Isn't det possible? Or is it just me that have missunderstod everything how it works?

    Edit: Either Iam to drunk, or...I cant find were I remove the pool? If I dc both hosts from the pool. I want to remove it too. When I connect the hosts to the XO they both goes into the same pool again 😕


  • XCP-ng Center Team

    @fraggan said in Trying to migrate:

    I want to be able to manage everything

    You can connect 100000000 hosts/pools to XO and all is in one place.

    share resources.

    please explain what you mean with that! We asked you that often in the last days. What do you meam with that? Which ressources?


  • XCP-ng Center Team

    @fraggan said in Trying to migrate:

    Either Iam to drunk, or...I cant find were I remove the pool?

    You have to remove the empty host from your pool, not the pool from XO.


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