[CentOS-virt] KVM virtual machine and SAN storage with FC

Wed Jul 3 05:40:37 UTC 2013
Brett Worth <brett.worth at gmail.com>

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 

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 

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.


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