[CentOS] OT: Recommendations for a virtual storage server

Mon Jan 31 03:05:55 UTC 2011
James A. Peltier <jpeltier at sfu.ca>

----- Original Message -----
| On 1/29/11 5:05 AM, carlopmart wrote:
| >>
| >> |>      It is very important that the virtual machine consumes the
| >> |>      least
| >> |>      resources
| >> |>   possible (host has 5GB RAM and i need to run three virtual
| >> |>   machines
| >> |>   minimum,
| >> |>   including this storage server as a virtual machine).
| >> |
| >> | What's the point of adding an extra virtual layer compared to an
| >> | nfs
| >> | or
| >> | iscsi share from the host (nfs if it is shared, iscsi if it is
| >> | the VM
| >> | image store)? This seems like it would be more efficient if you
| >> | run
| >> | exsi on the hardware with centos and the others as guests anyway.
| >> |
| >>
| >> There are some advantages that I can see in that if your hardware
| >> dies you can migrate the entire host and disks over to another
| >> VMWare hosts.
| >>
| >> If your NFS host is not H/A a loss of the host would take down the
| >> virtual machines too. Additionally, virtualization offers the
| >> ability to migrate the VM and disk to newer hardware somewhat
| >> transparently allowing you to take advantage of the
| >> latest/greatest/buggy tech.
| >>
| >> Just my 2c ;)
| >>
| >
| > Correct.
| 
| But I don't see how any of those things apply here. If the host fails
| your vm's
| are going to fail in any case, and there's not much magic involved in
| exporting
| an NFS share even if you need to move it. Iscsi targets are slightly
| more
| complicated because it's not included in the base Centos install but
| you can
| find howto's to set it up. When your resources are limited it looks
| like a big
| waste to add an unnecessary virtual layer to storage. I've done it the
| other
| way around, though, with NFS exports from the host being mounted by
| the guest VM's.
| 
| --
| Les Mikesell
| lesmikesell at gmail.com

I made no claims that it solved anything.  I merely noted why someone might want to virtualize in place of NFS.  Personally, I don't think that the OP really knows what they want, or they want the best of all worlds without compromise.  I don't see how it is possible to provide what is being asked for.  Really I think a minimum of two ideally a third server providing iSCSI or NFS is needed for the solution to work.  That third machine should have all of the possible host level redundancy possible to keep it running.  If H/A is required at least two machines are required.

-- 
James A. Peltier
IT Services - Research Computing Group
Simon Fraser University - Burnaby Campus
Phone   : 778-782-6573
Fax     : 778-782-3045
E-Mail  : jpeltier at sfu.ca
Website : http://www.sfu.ca/itservices
          http://blogs.sfu.ca/people/jpeltier