SUMMARY: Parallel DB, HA, and Sun cluster 2.1

From: Paul Robinson (
Date: Sun Feb 07 1999 - 15:06:25 CST

My original question:
I have a question, which I hope someone may be able to answer, one of
our clients has a nice little HA cluster going with oracle PDB, and sun
cluster 2.1.
Between the two machines is a private network, which is supposedly
low-latentcy... then interfaces come up as "scid" interfaces, i.e. scid0
and scid1.. We are looking to setting up a testing environment, similar
to this, but much smaller, but there's one question thats plaguing me,
thats is, what are the interfaces exactly?? the only thing i can get out
of the consultant handling, is that they are required by PDB, that they
are low latency, and he didnt really know if they were simple network
interfaces, or something more complex....

My other question is, would sun ATM 155 interfaces be good enuf to
handle the pdb in a small scale environment...

I got a few responces to this one, and thank you very much to all those
that replied.

The SCIzzl web page is and there is a great link
off there called "what is Scalable Coherent Interface"

The SCI in use by sun is made by Dolphin (
They are very low latency (<4us), they have a 200M/sec bandwidth, and
are quite cheap.

Im still not wholey sure if I can use another solution in the way of
network interfaces. From what i've been told, cluster 2.1 supports
ethernet (le, be, hme etc..) and sci. You are also not allowed to mix

However, if I understand correctly, PDB may very well require sci for
its shared memory arrangement, among other things. One person did quote
the course notes for me, stating that:
- SCI is a memory based interconnect which allows sharing of
- memory among cluster notes. The SCI IEEE 1596-1992 standard provides
- shared-memory abstractions and semantics by message passing, although
- the third-party Dolphin hardware does not support cache coherency. The
- Dolphin product is SBus based, with PCI products currently in
- development.
- The SCI technology was selected by Sun for use as a high-speed cluster
- interconnect based upon its high bandwidth, low-latency, and good
- scalability characteristics and future cluster roadmap requirements.
- I suspect if the software expects to see these, then you'll need them.

I suspect he is very much right for my needs.

Once again, thanks to all those that replied.


Paul Robinson ----- -----
Unix Systems Administrator  ---+++---  Access Systems Research Pty. Ltd.
Level 10, 20 Berry Street, North Sydney             Tel: +61 2 9957 1036
NSW 2060 Australia                                  Fax: +61 2 9959 5111

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