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

Thu Jul 4 04:44:05 UTC 2013
denis bahati <djbahati at yahoo.co.uk>

Hi Brett,

On my plan is as follows:

I have two machine (Server) that will host two VM each. One for database and one for application. Then the two machine will provide (Load Balance and High availability). My intention is that all application files and data file for the database should reside on the SAN storage for easy access and update.

Therefore the storage should be accessible to both VMs through mounting the SAN storage to the VMs. The connection between SAN storage and the servers is through Fiber Channel.

I have seen somewhere talking about DM-Multipath but i dont know if this can help or the use of VT-d if can help. I will also appreciate if you provide some links to give me insight of how to do this.

If you need more information, please let me know.


> From: Brett Worth <brett.worth at gmail.com>
>To: denis bahati <djbahati at yahoo.co.uk>; Discussion about the virtualization on CentOS <centos-virt at centos.org> 
>Sent: Wednesday, 3 July 2013, 8:40
>Subject: Re: [CentOS-virt] KVM virtual machine and SAN storage with FC
>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
>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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