[Linux-cluster] Quorum disk: Can it be a partition?

[RR]

On 11/10/06, Lon Hohberger <lhh at redhat.com> wrote:
> On Thu, 2006-11-09 at 13:40 +1000, RR wrote:
> > On 10/10/06, Robert Peterson <rpeterso at redhat.com> wrote:
> > > Yes.  You definitely want to use shared storage.
> > >
> > > Regards,
> > >
> > > Bob Peterson
> >
> > Hello,
> >
> > does anyone know if having this quorum disk on an iSCSI SAN which the
> > linux nodes can only access through an iscsi-initiator with non-TOE
> > NICs would cause any significant CPU usage?
>
> Qdisk is normally used to watch network paths and advertise via a
> non-network channel (i.e. a SAN) about a node's viability in the
> cluster...
>
> Using qdisk over iSCSI (or gnbd) is doable, but you'd have to have it on
> a private, iSCSI-only network for it to make any sense. (i.e. treat the
> iSCSI network as a SAN which only has SAN traffic).
>
> I don't know the implications of using TOE vs. non-TOE for your
> configuration.  Someone else will have to answer that one.
>
> -- Lon

Hi Lon,

thanks for the response. Yeah I have an isolated SAN where the iSCSI
targets reside and is serviced by stacked Cisco GigE switches and
there's nothing on this network besides iSCSI traffic.

You didn't say anything about if this can be an NFS type partition
(but that would probably not qualify as a non-network path) although
NFS also uses a fair bit of CPU but I have seen the CPU usage on a
Dual-Xeon 3.6Ghz computer go upto 44% (is there a way in Windows to
see usage per virtual CPU?) when transferring a 1GB file across the
network to the SAN over non-TOE NICs.