brad12341
2 Iron

VBUS and TID

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Hello,

I'm running an AIX 5.2 host connected to a dmx1000.
I ran the following command - symcfg -sid 1303 -dir 2b -p 0 list -address -available
Below are the partial results. I'm not sure what VBUS and TID are used for.

Symmetrix ID: 000xxxxxxxxx

Director Device Name Attr Address
---------------------- ----------------------------- ---- --------------
Ident Symbolic Port Sym Physical VBUS TID LUN
------ -------- ---- ---- ----------------------- ---- --- ---
FA-2B 02B
02C3 /dev/rhdisk5 (M) 0 00 001
0115 /dev/rhdiskpower0 (M) 0 00 002
011D /dev/rhdiskpower1 (M) 0 00 003
0125 /dev/rhdisk22 (M) 0 00 004
012D /dev/rhdiskpower3 (M) 0 00 005
0135 /dev/rhdiskpower4 (M) 0 00 006
013D /dev/rhdiskpower5 (M) 0 00 007
0145 /dev/rhdisk33 (M) 0 00 008
- AVAILABLE 0 00 009 *

I would use the following commands to map my next sym volumes -

map dev 14e to dir 2b:0 target=0, lun=009;
map dev 14f to dir 2b:0 target=0, lun=00a;
map dev 150 to dir 2b:0 target=0, lun=00b;

I just keep incrementing the lun number (next would be 00d) for each new maping.
What if I need to map hundreds more symm volumes. Can I just keep incrementing?
Is there a limit to the number of LUNs for target 0? At some point do I need to start using target 1 or target 2?
Again I'm not sure what VBUS and TID are used for.

Message was edited by: I removed the Symmetrix ID number.
KCSCP
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xe2sdc
4 Germanium

Re: VBUS and TID

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AFAIK Aix don't need vbus or target :D ..

With AIX you simply use the already mentioned (in the other thread) 12 bits as a single "namespace" to choose your lun address from. So with AIX you can choose any lun between 0x000 and 0xFFF ... No TID or VBUS needed.

However note that the "lun" you choose (0xBAD as an example) MAY be presented to an hpux host sharing the same port. The HPUX host (with the appropriate symmask magic wand) may also see your devices, translating you 0xBAD lun in VBUS=B TGT=A LUN=D .. Note however that HPUX may not see this device even if you mask it since the LUN value is outside allowed ranges (hmm that's why I choose a BAD lun ;-) ) .. If you need further help, feel free to ask :D
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dynamox
6 Gallium

Re: VBUS and TID

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xe2sdc
4 Germanium

Re: VBUS and TID

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AFAIK Aix don't need vbus or target :D ..

With AIX you simply use the already mentioned (in the other thread) 12 bits as a single "namespace" to choose your lun address from. So with AIX you can choose any lun between 0x000 and 0xFFF ... No TID or VBUS needed.

However note that the "lun" you choose (0xBAD as an example) MAY be presented to an hpux host sharing the same port. The HPUX host (with the appropriate symmask magic wand) may also see your devices, translating you 0xBAD lun in VBUS=B TGT=A LUN=D .. Note however that HPUX may not see this device even if you mask it since the LUN value is outside allowed ranges (hmm that's why I choose a BAD lun ;-) ) .. If you need further help, feel free to ask :D
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xe2sdc
4 Germanium

Re: VBUS and TID

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Message was edited by: I removed the Symmetrix ID
number.
KCSCP


Whoops I didn't notice that there was a symmid visible !!! Shame on me !!! :D
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brad12341
2 Iron

Re: VBUS and TID

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OK, currently our DMX does not have any HP-UX, only AIX. It sounds like I can simplify my current map command. Before I was using -

map dev 14e to dir 2b:0 target=0, lun=009;

now I can use
map dev 14e to dir 2b:0 lun=009; (leave the target off)

I can keep incrementing the lun by 1 until I hit FFF (I won't need to go that high as I will only have about 200 luns).

Does this sound correct?

Thanks - Brad
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dynamox
6 Gallium

Re: VBUS and TID

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sure, i can't even use target= value in my symconfigure scripts because my FAs do not have the v-bit enabled. If i add target=0 value to my scripts they simply fail complaining about improper target id or something of that nature.
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xe2sdc
4 Germanium

Re: VBUS and TID

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I totally agree with Mr Dynamox the great Jamaican King :-)
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MarcT2
2 Iron

Re: VBUS and TID

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I can keep incrementing the lun by 1 until I hit FFF (I won't need to go that high as I will only have about 200 luns).


Oh, that's a can of worms...

Many open systems hosts use "peripheral device addressing" and can only recognise the lower two nibbles of the LUN address (ie 000-0FF hex, or 0-255 decimal).

As far as I know this applies to Windows, Solaris (using the sd driver), Linux & Novell. Older versions of AIX with SCSI2 compliant fibre HBAs also fall into this category.

HP & Sequent hosts uses volume set addressing, where the most significant nibble becomes the VBUS, and therefore can make use of it. However with HP-UX, the least significant nibble (which the host interprets as it's lun value) must be in the range 0-7 (ie only xx0-xx7 is allowed).

Solaris with the Leadville (ssd) driver supports LUNs in the range 000-FFF, and the latest I can find about AIX is that we support LUNs from 000-0x1FF with the IBM 6228 adaptor (or later), which is SCSI-3 compliant.

Having said all that, EMC support up to a maximum of 512 LUNs per FA port on a DMX/DMX2 and up to 1024 on the DMX3. The LUN addresses can be above these limits, provided the total number of LUNs does not exceed the limit and the addresses are legal for the type of host attached.

See Knowledgebase article emc7896 for more details.

Hope that helps!
Marc
xe2sdc
4 Germanium

Re: VBUS and TID

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I can keep incrementing the lun by 1 until I hit

FFF (I won't need to go that high as I will only have
about 200 luns).

Oh, that's a can of worms...


In this case we have a lot less worms ;-) since we are talking about recent AIX versions :D .. However it's better to pinpoint all other possible limits we may fall into.. ThX :D
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dynamox
6 Gallium

Re: VBUS and TID

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Having said all that, EMC support up to a maximum of
512 LUNs per FA port on a DMX/DMX2 and up to 1024 on
the DMX3. The LUN addresses can be above these
limits, provided the total number of LUNs does not
exceed the limit and the addresses are legal for the
type of host attached.


Marc, the 512 LUNs limit ..does that take into account meta heads only or it counts meta members as well ?

Thanks
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