SUMMARY: Clustering

From: John Bradley (
Date: Thu Oct 02 1997 - 12:06:59 CDT

Thanx to:

Gregg Ferguson [LA Aerospace SE]" <gregg.ferguson@West.Sun.COM
Lori <Lori.Blake@Frogtown.Com
Marks, Evan R" <>
Rogerio Rocha - BVL - Lisbon Stock Exchange -I.S." <>
Glenn Satchell - Uniq Professional Services <>
Bill Kamps <>
Robbins, Garry" <>


> Can anyone recommend some software that would allow me to share a
> SPARCstorage Array with 2 servers, or maybe share 2 SPARCstorage Arrays
> with 2 servers. Also something that would do clustering between 2 or
> more servers to share Data, Apps, NIS+, Oracle, etc.


Gregg Ferguson, our Sun Eng. Rep. gave a pretty good explination below.
Also included are the replies I got.

2 Servers with 1 SPARCstorage Array: You can't access the data at the
same time but you could use the volumes created on the Array by
exporting/importing disk groups with vxva (Volume Manager, shipped with

Clustering machines to share data and applications: Use some High
Availability (HA) type of software. Sun has a version and Qualix makes
a couple of different types (Datastar, HA).




       "Gregg Ferguson [LA Aerospace SE]" <gregg.ferguson@West.Sun.COM>
       gregg.ferguson@West.Sun.COM, sher.khan@West.Sun.COM,

Hi John,

It depends on what you are aiming for -- is it high availability

You can share a SPARCstorage Array (SSA) between 2 systems.
Enterprise Volume Manager (EVM) will help you do this but
you will need extra hardware if you don't already have it --
a second optical rx/tx card for the SSA (this is our
part # X595A) and a Fibre-Channel card w/ cable for the 2nd system
(X1057A). The "sharing" would only allow for each disk to
be owned and accessed by one of the two systems (although the
disk could be reassigned to the other system through importing
and exporting the Volume Manager's disk groups).

If High Availability is what you are after, Sun sells software
that allows 2 systems to back up each other for NFS, Oracle,
etc. and has an API for your own apps to take advantage of
this. You can also do NIS+ via backup servers.

If you are looking for load sharing over 2 or more
systems, we sell HPC software for High Performance Computing
that includes load-balancing and controlling software,
including messaging libraries for your apps (MPI and PVM).

I hope this helps. Let me know more specifically what you
are looking for and what equipment you already have that
you want to cluster together.

   -- Gregg Ferguson


           CHENTHIL KG <>
           John Bradley <>





You can already share the SSA's from a hardware perspective. Just
get a second optical module and dual port the SSA. Veritas
Volume Manager will simplify the software aspects of hardware sharing.
I'm unaware of anything that will let you access the same disk
simultaneously though. I'm pretty sure Sun doesn't support multi-
initiator SCSI.

When you say clustering do you mean as in dynamically allocating
resources, or just failover? For failover I suggest Firstwatch from
Veritas. Sun does have some real clustering software, but it is
very dependant on hardware config, I think you have to buy their
hardware clustering solution.

Rick Reineman
Lasers CAD&UNIX Systems Management
Lawrence Livermore National Laboratory


           John Bradley <>

The SUN PDB solution does what you want
for ORACLE data. We have 2 Ultra/4000s
sharing 4 SAs running ORACLE Applications
with the ORACLE Parallel Server option.

The PDB 1.2 software won't share file systems
at the moment, but apparently that issue
will be solved in an upcoming release.

Currently, SUN clusters are limited
to 2 nodes, but again, word is that
that restriction will be lifted
to allow more nodes.


       Bill Kamps <>
       John Bradley <>

We use FirstWatch from Veritas with two sparc storage arrays shared
between two sparc 20's. You can visit them at


       Glenn Satchell - Uniq Professional Services

I can suggest two strategies for you.

The first is the simplest, in that you can have two fibre interfaces in
a storage array and connect one to each host. Disksuite and Volume
Manager each know how to handle a subset of disks, correctly handling
reserve and release. Unfortunately any one disk can only be accessed
from one system at a time.

The second method is to use a very clever piece of software we wrote.
We call it the UP File System (UPFS for short). UPFS allows a single
mount point to have a number of members which all receive a copy of any
updates. The underlying members can be NFS so that you can do remote

For full details see our web site, Let me know if you
have any further questions. The software is available with an
evaluation license if you want to try it out. The details we require
are on the web page.


Glenn Satchell  |
Uniq Professional Services Pty Ltd    ACN 056 279 335  | In a world with
PO Box 70, Paddington,  NSW 2021,  (Sydney) Australia  | no fences who
Phone 02 9380 6360 Pager 016 287 000 Fax 02 9380 6416  | needs Gates?


From: " Rogerio Rocha - BVL - Lisbon Stock Exchange -I.S." <> To: John Bradley <>

I do not recommend, as I just started today looking at Best regards, Rogerio Rocha BVL - Lisbon Stock Exchange Information Systems


From: "Marks, Evan R" <> To: "'John Bradley'" <>

do you need access to both simultaneously? If not look into Qualix HA+, Veritas Firstwatch or Solstice HA...

The Veritas Volume Manager alone allows you to multihome your arrays and you can just deport and import disk groups between machines when needed


From: Lori <Lori.Blake@Frogtown.Com> To: John Bradley <>

Sun has a high-availability solution , forget what it's called, probably part of solstice.

my company is considering qualix, but I don't know anything about i, I'd rather stick with sun's software, but I'm going to wait and be open minded.


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