Discussion:
MSA30 single/dual bus
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Joukj
2017-03-02 09:09:20 UTC
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Hi

I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable I
only see half of the disks. I still had a SCSI card from a single bus
type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?

regards
Jouk
Eberhard Heuser
2017-03-02 09:26:20 UTC
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Post by Joukj
Hi
I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable
I only see half of the disks. I still had a SCSI card from a single
bus type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?
regards
Jouk
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The interface, that definitely works is:

Compaq 70-40453-01

with one scsi-connector.

Eberhard
Joukj
2017-03-02 10:34:41 UTC
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Post by Eberhard Heuser
Post by Joukj
Hi
I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable
I only see half of the disks. I still had a SCSI card from a single
bus type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?
regards
Jouk
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http://rbnsn.com/mailman/listinfo/info-vax_rbnsn.com
Compaq 70-40453-01
with one scsi-connector.
Sure, but let's fomulate the question slightlu different;
Is the SCSI module (i.e. the one mentioned by Eberhard) the only
difference between a single and a dual bus?

Regards
Jouk
Joukj
2017-03-10 11:22:57 UTC
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Post by Eberhard Heuser
Post by Joukj
Hi
I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable
I only see half of the disks. I still had a SCSI card from a single
bus type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?
regards
Jouk
_______________________________________________
Info-vax mailing list
http://rbnsn.com/mailman/listinfo/info-vax_rbnsn.com
Compaq 70-40453-01
with one scsi-connector.
Eberhard
Sure,but... The one I had appeared to be malfunctioning, although all
the control leds were "green".
Took me some time to get another one, but by placing this one I could
see all the disks.
So SB<->DB is just replacing the SCSI-module.

regards
Jouk

Stephen Hoffman
2017-03-02 16:23:52 UTC
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Post by Joukj
I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable I
only see half of the disks. I still had a SCSI card from a single bus
type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?
Various DEC SCSI enclosures were routinely sold in single and split-bus
configurations. Details and conversions varied by model or enclosure.
Some were permanently single-bus, some where split-bus, and some of
the split-bus configurations could be reconfigured to a single bus by
moving a backplane jumper pack or board.

I'm sure some folks have thought about being able to reconfigure the
SCSI bus backplane entirely in software too, but I've not seen one of
those available from DEC.

For the MSA30 series and specifically the MSA30-MI, see the dual-bus
discussion in
http://h18000.www1.hp.com/products/quickspecs/archives_Division/11967_div_v12/11967_div.PDF
— "or provides access from two different servers to two separate
storage areas.". The MI configuration was one of the very few "recent"
SCSI enclosures capable of and supported for multi-initiator
operations; of shared SCSI bus configurations in a cluster;
--
Pure Personal Opinion | HoffmanLabs LLC
Joukj
2017-03-03 08:06:51 UTC
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Post by Stephen Hoffman
Post by Joukj
I have a MSA30.It seems to be a dual bus: if I connect the SCSI cable
I only see half of the disks. I still had a SCSI card from a single
bus type and tried to swap. This resulted in seeing none of the disks
Question: is this normal behaviour or is the SCSI card broken?
Various DEC SCSI enclosures were routinely sold in single and split-bus
configurations. Details and conversions varied by model or enclosure.
Some were permanently single-bus, some where split-bus, and some of the
split-bus configurations could be reconfigured to a single bus by moving
a backplane jumper pack or board.
I'm sure some folks have thought about being able to reconfigure the
SCSI bus backplane entirely in software too, but I've not seen one of
those available from DEC.
For the MSA30 series and specifically the MSA30-MI, see the dual-bus
discussion in
http://h18000.www1.hp.com/products/quickspecs/archives_Division/11967_div_v12/11967_div.PDF
— "or provides access from two different servers to two separate storage
areas.". The MI configuration was one of the very few "recent" SCSI
enclosures capable of and supported for multi-initiator operations; of
shared SCSI bus configurations in a cluster;
Thanks Hoff for pointing me to the info.

regards
Jouk
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