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Various Cluster Questions?

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The Question is:

I am responding to a tender that will replace three AS8400's that are clustered
 running OpenVMS V7.1 ( two machines in one location and another 20 KM away
 connected via Gigaswitches and FDDI ). Storage is HSJ based and three way
 mirroring via volume shado
wing is used.
New Alphas, two per site and Fibre Channel Storage at each site is being
 proposed to replace the current equipment.
The current DataVault FDDI service used for Cluster/LAN traffic is being phased
 out and Gigabit ethernet is being proposed as its available from a local
 Communications provider ( ATM at this point is too expensive ).
My questions are :-
1) What is the max distanced Gigabit ethernet clusters can be run over, I
 beleive its 240KM is this true, are there any obvious restrictions not
 mentioned in the clustering manuals.
2) Jumbo frame sizes are supported in V7.3 ( ~7000Bytes ) will this improve
 cluster traffic speeds over a standard Gigabit Ethernet shared service from a
 local Telco. What are the other advantages.
2) The service provider has quoted around a 2ms delay over the 20Km link
 between sites- is this OK for Cluster traffic between the two sites assuming
 the gigabit switches at either end will support autonegotiation.
3) Volume shadowing will need to run between sites I'm assuming that because
 mount verify timeout values start at 1 second that 2ms delays will not be an
 issue for any minimerge / copy operations ( around 20 shadow sets planned )??
 are there any potential
 issues ??
4) Are there any reference sites running multisite clustering over Gigabit
 Ethernet via Telco connections, are detailed configurations available ? - who
 are the customers ?
5) Are there any Specific whitepapers etc on Gigabit Ethernet Multisite
 Clusters with Fibre Channel Storage. ( Not interested in CI DSSI SCSI etc )
Any help on the Above questions would be greatly appreciated.
Barry Thompson

The Answer is :

  1: Please see the OpenVMS Cluster Software Product Description (SPD)
     for the current maximum supported diameter.  Between the SPD and
     the manuals, the OpenVMS Wizard expects the "obvious restrictions"
     will be listed.
  2: Unclear, whether or not the larger frames are useful depends on
     the traffic.
  3: The Mount Verify Timeout setting depends on the site-specific
     trade-offs between requirements for ride-over vs rapid fail-over.
  4: Yes, but you already knew that you were not likely to receive a
     pointer to a reference site via the Ask The Wizard area.
  5: A cluster is a cluster is a cluster.  Read the existing cluster
     manual.  If you wish to know about Fibre Channel requirements,
     read the Fibre Channel manual referenced in the FAQ.

answer written or last revised on ( 29-MAY-2001 )

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