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Replacing Memory Channel with Gigabit Ethernet

 
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Bruce Aschenbrenner
Occasional Visitor

Re: Replacing Memory Channel with Gigabit Ethernet

I'm getting ready to do the same thing.
Current have Memory Channel between 2 buildings 1200' apart. One node (2 node cluster) is moving 20 miles away. I've opted for using 2 gig-e connections. They will be point-to-point connections.

A suggestion I got from HP was to add the following line in SYSTARTUP_VMS.COM:

$ MCR SCACP SET LAN /PRIORITY=10 EWA

and since I will have two:

$ MCR SCACP SET LAN /PRIORITY=10 EWB

It's not a permanet setting, that's why it needs execute at startup.
John Gillings
Honored Contributor

Re: Replacing Memory Channel with Gigabit Ethernet

re comarow:

>An interesting factor. While 100 mb
>cards were recommended to hard code
>fast full duplex, as digital/hcompaq
>didn't conform to standards, on
>gigabit ethernet use autonegotiate.

Not true. There were no standards that digital/hcompaq didn't conform to! I don't know where it came from, but "Alpha's don't support autonegotiation" is now, and has always been, a myth.

The recommendation from HP Customer Support Centres is to use autonegotiate for ALL NICs and switch/hub ports. Hard setting your cards to 100/Full will NOT work if the switch port is set to auto.

The rule is that both NIC and switch port MUST be set the same. Either both hard set to a specific speed and duplex, or both set to autonegotiate. Since most modern switches and hubs will have autonegotiate by default, that's what you should set your OpenVMS systems to.
A crucible of informative mistakes
Bart Zorn_1
Trusted Contributor

Re: Replacing Memory Channel with Gigabit Ethernet

Ian Miller wrote:

"keep the GBE used for cluster traffic away from the network people - they often don't understand the availability requirements or the fact that its not IP and can cause trouble."

This is indeed a big problem. One might even consider using an other brand of switches (E.g. Digital Networks when the whole company is using Cisco). That way it may be easier to argue that these are part of the system and not the network.

YMMV,

Bart Zorn
Jan van den Ende
Honored Contributor

Re: Replacing Memory Channel with Gigabit Ethernet

Re Ian & Bart:

Let me one again bring Tom Speake in the floodlight.

He once was Manager Disaster Tolerant Computing at Digital.

He did seminars on DT then.

His basic rule then was (and he still holds on to that as per our meeting again atlast Bootcamp):

The Cluster Interconnect is __NOT__ a network connection. It is the __SYSTEM BUS__.
-- even though it might be 800 KM long, and use network hardware --

We have fought hard to get it accepted, but have been VERY happy with it on more than one occasion!

Please, anybody, feel free to quote Tom on this, he still feels proud for every implementation that his text has helped to realise!

Proost.

Have one on me.

jpe
Don't rust yours pelled jacker to fine doll missed aches.
comarow
Trusted Contributor

Re: Replacing Memory Channel with Gigabit Ethernet

John,

I'd be glad to discuss that with you. That was advise from the NSU group and years of getting clusters going.
John Robles_1
Occasional Visitor

Re: Replacing Memory Channel with Gigabit Ethernet

the FDDI has an up to 200Mbps thru put and is capable of 124 miles transmission without losing stamina. Laser optic option as opposed to multi-light one would be the preferred optic setting. If you are running 7.3 or above, multi protocol is supported for 7 modes of media transmission - CI, FDDI, CDDI, DSSI, SCSI, MC, FC, GbEther.. my 2 cents. This fddi should be an inexpensive option that you can find on "used-car" lots.

jzr