RE: Clustering: switches reliability/redundancy


> -----Original Message-----
> From: JF Mezei [mailto:jfmezei.spamnot@xxxxxxxxxxxx]
> Sent: December 14, 2005 3:44 PM
> To: Info-VAX@xxxxxxxxxxxx
> Subject: Clustering: switches reliability/redundancy
>
> In the very old days, one depended on the AUI to Thickwire device for
> each node. Failure would break the connection of one node and possibly
> jeoperdize quorum.
>
> Then came thinwire which was totally inert and as long as
> nobody touched
> the wire, it was not a point of failure.
>
> (although many would argue otherwise in practice, but in theory there
> was nothing to fail).
>
> Then comes along twister pair with the hub and later
> switches. Hubs and
> switches are powered.
>
>
> Are there considerations if a cluster nodes are all connected via the
> same switch/hub ? It the later fails, the whole cluster hangs and
> becomes inaccessible.
>
> Are hubs/switches considered "fault tolerant" ? If not, what possible
> steps would a good site planner take to ensure a cluster isn't
> jeoperdized by some $50 switch/hub ?
>
> Are hubs considered more "fault tolerant" than switches ?
>
> Is it just a simple case of reserving spare ports on a backup
> switch so
> that cluster ethernet connectiosn can be moved one by one before the
> main switch/hub is powered off for maintenance etc ?
>

JF,

Simple solution is to establish VLAN between 2 trunked switch/routers
and use separate NIC connections to each from each server. This causes
the switch to appear as a logical unit or virtual cluster interconnect
box. Entire switch/rtr fails and OpenVMS cluster keeps running i.e. not
even any application failover issues.

With the right IP failover config's in place, you would not even lose a
telnet connection.

OpenVMS will load balance SCS across all configured and available
connections. By configured I mean not disabled with the SCACP utility.

Regards

Kerry Main
Senior Consultant
HP Services Canada
Voice: 613-592-4660
Fax: 613-591-4477
kerryDOTmainAThpDOTcom
(remove the DOT's and AT)

OpenVMS - the secure, multi-site OS that just works.
.

Relevant Pages

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  • Clustering: switches reliability/redundancy
    ... Failure would break the connection of one node and possibly ... jeoperdize quorum. ... Then comes along twister pair with the hub and later switches. ... Are there considerations if a cluster nodes are all connected via the ...
    (comp.os.vms)
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