4 Operator

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2.8K Posts

August 1st, 2008 05:00

Don't think to luns, targets and vbus as something coming from Mars ;-) ...

With both Volume Set Addressing and Peripherial Addressing you have a grand total of 12 bits .. With peripherial addressing you use all 12 bits as your "lun address". With Volume Set Addressing the same 12 bits are split in 3 different "parameters" that we know with the common name of "target", "lun" and the misterious "vbus".

HPUX (it's the only OS I know that needs v-bit) uses the "vbus" (in conjunction with parameters gathered from the SAN) to form virtual SCSI controllers. That's how an hpux host can see up to 4096 different devices. The host will see 128 devices for every virtual controller .. but will also see up to 16 virtual controllers (depending on the 16 Vbusses) from every FA port ;-)

I think it's covered also elsewhere .. However here you can find a summary of what we already discussed elsewhere ;-)

Message was edited by:
Stefano Del Corno

4 Operator

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2.8K Posts

August 1st, 2008 05:00

Disregard my previous posts .. I was simply talking without correct figures .. However an hpux host can see MORE then 128 luns per HBA/FA and now you know how ;-)

4 Operator

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2.8K Posts

August 1st, 2008 05:00

16*128=2048 .. but every HBA may see multiple FA ;-)

Where did you see that hpux have a max of 256 lun per HBA ??

1 Rookie

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108 Posts

August 1st, 2008 05:00

I think VBUS ranges from 0-F, thats how we can have 2048 devices. my calculation is like 16 * 128 (TIDs 16 (0-F) * 8 LUNS (0-7))

But Visible LUNs per HBA is 256 on HPUX.

1 Rookie

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108 Posts

August 1st, 2008 05:00

Sorry not exactly right.

Visible LUNS per HBA on 11iV1 = 320(HA) or 512 (Non-HA) and 1536 on V2.

These are in Host connectivity guide

1 Rookie

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108 Posts

August 1st, 2008 06:00

Yes, Thanks a lot. I got the answer... :-)

2 Intern

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1.3K Posts

August 3rd, 2008 13:00

I think this is what meant by discussed else where

https://forums.emc.com/forums/thread.jspa?threadID=67674&start=0&tstart=0

Ajay,

did u get the logic how it is possible? not just what the guide says

Visible LUNS per HBA on 11iV1 = 320(HA) or 512 (Non-HA) and 1536 on V2.

what is meant by HA here?

4 Operator

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2.8K Posts

August 4th, 2008 00:00

HA = High Availability .. AFAIK :-)

1 Rookie

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108 Posts

August 4th, 2008 03:00

yes HA means High Availability.

I did get the logic for Visible Luns per HBA. I understand the number of Adresses available on each FA port with Volume set Adressing enabled.

2 Intern

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1.3K Posts

August 4th, 2008 18:00

I did not understand the context of HA in 11v1. (interms of OS version )

4 Operator

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2.8K Posts

August 5th, 2008 07:00

If you have a cluster running on hpux 11v1 nodes, each node can see up to xxx devices .. if you have standalone nodes, each node can see up to yyy devices .. :D
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