Re: KVM virtual machine and SAN storage with FC

Brett Worth <brett.worth@xxxxxxxxx> · Wed, 03 Jul 2013 15:40:37 +1000



    On 03/07/13 15:22, denis bahati wrote:

    
      Is there any body got
          any experience on setting up a virtualized environment in
          which the vm's can access a fiber channel SAN storage
          connected to host? the host access the SAN through its own
          HBA, but the hba is not recognized inside the virtual
          machines. Please let me know the step to go through this.

      
    How you use this storage depends on whether you plan to do migration
    from one server to another.

    
    If you're not going to be migrating then you can just allocate the
    FC LUN to LVM volume group and carve off logical volumes for the KVM
    VMs to use.  These can then have meaningful LVM names in
    /dev/vg_(VG)/lv_(LV) that can be allocated to the VM. See
    system-config-lvm.

    
    If you're planning to migrate between machines then the LVM solution
    is not going to work.  In that case then you might need to create
    volumes on you FC controller that will be seen as individual
    devices/luns on the host servers.  There is a consistent device name
    that can be used that appears under /dev/disk/by-id. This will be
    identical on any host servers that can see that volume.  This can be
    allocated to the VM and will be consistent for a migration.  Using
    this method requires careful management and meticulous documentation
    of which LUNs have been allocated to which VM.  The lun ids are not
    very user friendly.

    
    We've also have good results with DRBD for times when you want to be
    able to migrate between machines but do not have a SAN.  You have
    to  allocate all the storage on each server but you gain by having a
    sort of backup.

    
    Finally, I can recommend convirt as a good system manager interface.

    
    Regards

    Brett

    
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