[ovirt-users] fileserver as a guest oVirt

Thu Jul 17 12:33:29 UTC 2014

Hello,

for some reason the message was flagged spam; so there was a deplay.

oVirt supports direct LUNs. These LUNs are often already partitions of
some RAID enclosure.
AFAIK the MSA60 is a JBOD. You can use the p411 controller to create
your partitions / LUNs.

The Virtio-SCSI paravirt driver supports a wide range of (=most) SCSI
commands. This way clients can access them as 'real' SCSI devices.

If you did partition the LUN with parted, then the client(s) will see
these partitions also, along with the file system on it. 

As you might know, you cannot have 'normal' file systems mounted rw on
several machines at one, you need a cluster file system; see examples in
[1]; there are several open source FS's around.

Also, nothing stops you from mounting a file system read only on several
hosts.

One note on the subject, though:
I consider shared disk file systems as 'old' approach. I support them in
our setup because of historical reasons. 
Today in a new deployment I would tend to use more 'modern' scale out
file systems like GlusterFS (support in oVirt is quite well) or
Ceph/Rados as object store file system. Using the native clients, you
basically have a shared disk file system with less bottlenecks (MDC's in
shared disk fs). Also, both examples have APIs - an application using
this can greatly benefit in performance. Again, I consider using APIs
for file storage the approach of the future.

If you need to attach NFS / CIFS clients, you can always reshare these
file systems and use (p)NFS or CTDB if you want to cluster this.

Note, with one host and one JBOD this makes little sense to me.

[1] http://en.wikipedia.org/wiki/Clustered_file_system
[2] https://ctdb.samba.org/

On Mo, 2014-07-14 at 08:10 +0000, Niklas Fondberg wrote:
> Thanks, after reading it makes sense. I suppose I need to drop my hope of
> having sharing possibility with the host.
> I have two questions that you might be able to answer:
> 1. Does direct LUN support partitions or only whole devices
> 2. Do you know of any open source way of making them shareable to Ovirt?
> 
> My setup is simple:
> - HP DL380 with dual Xeon and lots of RAM. Boots from seperate disk (USB)
> - MSA60 with p411 attached to the HP DL380
> 
> When we grow oVirt we will grow with DL360¹s and use all shared storage
> from the guest fileserver on the first host.
> 
> 
> 
> On 14/07/14 08:57, "Daniel Helgenberger" <daniel.helgenberger at m-box.de>
> wrote:
> 
> >Hello,
> >
> >just add my 2ct: I did a lot of bench marking for our SAN (FC LUN's). I
> >also need file servers for our SMB Clients.
> >
> >I recommend using Direct Attached LUNs for your purpose and attach them
> >to the VMs as VirtIO-SCSI disks. You can even added them as shareable to
> >oVirt if you deploy some kind of SAN file system (we use Quantum's
> >StorNext).
> >
> >Bottom line, the implementation of VirtIO-SCSI is so well done and
> >support in oVirt is great. I cound not see any bottlenecks in the
> >visualization. For the foreseeable future I will not deploy bare metal
> >file Servers again.
> >
> >HTH,
> >
> >On So, 2014-07-13 at 15:47 +0000, Niklas Fondberg wrote:
> >> 
> >> From: Karli Sjöberg <Karli.Sjoberg at slu.se<mailto:Karli.Sjoberg at slu.se>>
> >> Date: Sunday 13 July 2014 14:51
> >> To: Niklas Fondberg <niklas at vireone.com<mailto:niklas at vireone.com>>
> >> Cc: "users at ovirt.org<mailto:users at ovirt.org>"
> >><users at ovirt.org<mailto:users at ovirt.org>>, Karli Sjöberg
> >><Karli.Sjoberg at slu.se<mailto:Karli.Sjoberg at slu.se>>
> >> Subject: Re: [ovirt-users] fileserver as a guest oVirt
> >> 
> >> 
> >> Den 12 jul 2014 22:49 skrev Niklas Fondberg
> >><niklas at vireone.com<mailto:niklas at vireone.com>>:
> >> >
> >> >
> >> >
> >> > On 12 jul 2014, at 16:57, "Karli Sjöberg"
> >><Karli.Sjoberg at slu.se<mailto:Karli.Sjoberg at slu.se>> wrote:
> >> >
> >> >>
> >> >> Den 12 jul 2014 15:45 skrev Niklas Fondberg
> >><niklas at vireone.com<mailto:niklas at vireone.com>>:
> >> >> >
> >> >> > Hi,
> >> >> >
> >> >> > I'm new to oVirt but I must say I am impressed!
> >> >> > I am running it on a HP DL380 with an external SAS chassi.
> >> >> > Linux dist is Centos 6.5 and oVirt is 3.4 running all-in-one (for
> >>now until we need to have a second host).
> >> >> >
> >> >> > Our company (www.vireone.com) deals with system architecture for
> >>many telco and media operators and is now setting up a small own
> >>datacenter for our internal tests as well as our IT infrastructure.
> >> >> > We are in the process of installing Zentyal for the SMB purposes
> >>on a guest and it would be great to have that guest also serving a fs
> >>path directory with NFS + SMB (which is semi crippled on the host after
> >>oVirt installation with version 3 et.c.).
> >> >> >
> >> >> > Does anyone have an idea of how I can through oVirt (seen several
> >>solutions using virsh and kvm) letting my Zentyal Ubuntu guest have
> >>access to a host mount point or if necessary (second best) a seperate
> >>partition?
> >> >> >
> >> >> > Best regards
> >> >> > Niklas
> >> >> >
> >> >>
> >> >> Why not just give the guest a thin provision virtual hard drive and
> >>expand it on a demand basis?
> >> >>
> >> >> /K
> >> >
> >> > Thanks for the advise but this would not suite us I'm afraid. It
> >>would be difficult wrt incremental backups as well as host machine
> >>file-routines.
> >> >
> >> >
> >> 
> >> Well, going by Occam's raizor; the simplest answer is usually correct.
> >>Can't really tell what you mean by file-routines but backups would be
> >>well served by snapshots (can't get more incremental than that) and
> >>disaster recovery could be as easy as a rsync from inside the guest to a
> >>remote machine.
> >> 
> >> The biggest pros here is the ease of being able to setup an export
> >>domain, attach, export the VM, detach domain, and then attach and import
> >>to a "real" setup when the AIO starts feeling crowded later on. Thinking
> >>ahead is never a bad thing, no?
> >> 
> >> /K
> >> 
> >> Thanks for your suggestions!
> >> The thing also is that the performance will be very bad if we have the
> >>25TB SAS array shared for our purposes (lots of media streaming) using a
> >>virtual disk.
> >> What I am after (after more reading) is support for virtio-9p-pci
> >>(http://www.linux-kvm.org/page/9p_virtio) using oVirt. Alternative is
> >>the Direct LUN hook (http://www.ovirt.org/VDSM-Hooks/directlun, if I can
> >>figure out how to work with hooks...)
> >> Any chance anybody has an answer for these questions?
> >> 
> >> _______________________________________________
> >> Users mailing list
> >> Users at ovirt.org
> >> http://lists.ovirt.org/mailman/listinfo/users
> >
> >-- 
> >
> >Daniel Helgenberger
> >m box bewegtbild GmbH
> >
> >P: +49/30/2408781-22
> >F: +49/30/2408781-10
> >
> >ACKERSTR. 19 
> >D-10115 BERLIN 
> >
> >
> >www.m-box.de  www.monkeymen.tv
> >
> >Geschäftsführer: Martin Retschitzegger / Michaela Göllner
> >Handeslregister: Amtsgericht Charlottenburg / HRB 112767 
> 

-- 

Daniel Helgenberger 
m box bewegtbild GmbH 

P: +49/30/2408781-22
F: +49/30/2408781-10

ACKERSTR. 19 
D-10115 BERLIN 

www.m-box.de  www.monkeymen.tv 

Geschäftsführer: Martin Retschitzegger / Michaela Göllner
Handeslregister: Amtsgericht Charlottenburg / HRB 112767 
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