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Which disks are in which LUN?

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M Dijsselbloem
Occasional Contributor

Which disks are in which LUN?

Hi Gurus,

We hava a va4700 array and want to know which disks are in use by which LUN ID???s. I???ve tried to find it out by using lssf /dev/dsk/*. It shows me a lot of disks, HW paths and LUN ID???s, however I only see LUN ID???s from 0 to 7 and we have 22 LUN???s.
I also see HW paths with ???address ??? /dev/dsk/c4t0d6??? instead of ???address 0/3/0/0.8.0.21.0.0.0 /dev/dsk/c5t0d0???. In ioscan ???fnC disk have all disks status ???CLAIMED???.
Is there a way to find this out?

Greetings,

Mark
4 REPLIES
Eugeny Brychkov
Honored Contributor
Solution

Re: Which disks are in which LUN?

Mark,
1. LUNs are spread across all physical disks in VA. This means there're no LUN dedicated disks in disk set (remember: there're 2 disk sets in VA7400 called redundancy groups: RG1 and RG2);
2. LUNs are represented to OS as ordinary SCSI disks, this means that for each LUN you will see usual device files (as you mentioned). But FC has an extension (you remember usual SCSI can have only 8 LUNs) and LUN numbers are coded into three last values in device path. Example:
0/3/0/0.8.0.21.0.1.5
0/3/0/0 is a hardware path where HBA is installed at (usually slot)
8.0 private loop identifier
21 loop-id
0.1.5 LUN number coded, use formula 0*128+1*8+5=13, so this hardware path is for VA7400's LUN #13
Eugeny
Eugeny Brychkov
Honored Contributor

Re: Which disks are in which LUN?

Forgot one thing about device file.
In this example device file will be
/dev/[r]dsk/c5t1d5
0.1(=t).5(=d)
value for 'C' is taken from SCSI controller instance number (in this case c5, looking to your example)
Eugeny
M Dijsselbloem
Occasional Contributor

Re: Which disks are in which LUN?

Thanks Eugeny,

This is what I'm looking for.

Brian M Rawlings
Honored Contributor

Re: Which disks are in which LUN?

Wow. I thought I might be able to add something, but Eugeny really nailed it.

The only thing I might add is a question: shouldn't such an excellent answer be worth a few seconds to assign points? Maybe even the magic rabbit? (8, 9, or 10 pts make it appear).

This would also help others searching the ITRC posts to quickly find this very useful information. I don't mean to be pushy about this, it's just a suggestion.

Nice post(s), Eugeny!

Regards, --bmr
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