XenServer 6.1 Limitations

1. Marco

   July 3, 2013, 7:50 am

   Hi and thanks for bloggin!

   Do you know if it’s possible to get greater VMs then 2 TB?
   Is it possible to bypass this limit? If not: Is it possible to
   merge several disks within a VM?

   What I need is a VM with one Volume and 5.5 TB.

   Best regards
   Marco

   • A Pablo Legorreta

     July 9, 2013, 10:03 am

     Marco,

     Although it is possible to create VMs greater than 2TB it is not officially supported. The way to bypass this limit is by using the following procedure:

     Find the uuid of the SR:
     root@xen~]# xe sr-list
     uuid ( RO) : a55e5f09-8fef-4b5d-8dae-9410d630f205
     name-label ( RW): SATA Drive1
     name-description ( RW): Hardware HBA SR
     host ( RO):
     type ( RO): lvmohba
     content-type ( RO):

     Get the volume group device name:
     root@xen~]# vgs | awk ‘{print $1}’ | grep a55e5f09-8fef-4b5d-8dae-9410d630f205
     VG_XenStorage-a55e5f09-8fef-4b5d-8dae-9410d630f205

     Create a new logical volume, with a proper name:
     Change the volume size (5T in example below) to specify the size of your VDI
     root@xen~]# lvcreate -L5T -n”LV-“$(uuidgen) VG_XenStorage-a55e5f09-8fef-4b5d-8dae-9410d630f205
     Logical volume “LV-4e3da1e4-9e1a-4e12-96a1-d3c233efc0d5” created

     Scan the SR:
     root@xen~]# xe sr-scan uuid=a55e5f09-8fef-4b5d-8dae-9410d630f205

     I am not aware of any way to merge multiple disks within a VM.

2. Marco

   July 30, 2013, 7:28 am

   Hi Pablo

   Big thx for your help 🙂
   It was not so easy to say the vm, that it have to use the new volume now,
   but with a small workaround I shaked the baby.

   I think it’s fair to post here the important steps, so further visitors
   with the same problem can access this info directly.

   Okay let’s start, after creation of the new volume with steps above I did this:

   1:
   – Create new VM in XenCenter
   – Choose small disk
   – Insert OS-install-cd
   – Start VM, wait till setup-screen appears

   2:
   – Choose storage-tab for the new vm -> attach the big disk
   – Delete the small setup-disk

   3:
   Now we’re not able to start the VM again, because the bootloader does not
   find the correct disk. Make sure the DVD-Option is still selected in Bootmenu
   for the new VM.

   4:
   – Change to the console of the xenserver and execute:
   # xe vm-param-set HVM-boot-policy=BIOS\ order uuid=UUID-OF-YOUR-NEW-VM

   5:
   Start your VM and install the new OS by using the new big disk

   Best regards
   Marco

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