Device WWN is NULL or empty

Question

Hi

I am getting device wwn as empty or null(marked in block letters below) while executing symdev list -v. It is expected behavior

Device Physical Name : Not Visible

Device Symmetrix Name : 0084 (CKD)
Device Serial ID : N/A
Symmetrix ID : 00019010xxxx

Device Group Name : MFDB2PROD
Device Logical Name : DEV027

Attached BCV Device : N/A

Attached VDEV TGT Device : N/A

Vendor ID : EMC
Product ID : SYMMETRIX
Product Revision : 5771
Device WWN :
Device Emulation Type : CKD-3390
Device Defined Label Type: N/A
Device Defined Label : N/A
Device Sub System Id : 0x2000
Cache Partition Name : N/A
Device CU Image : 0x00

Device Block Size : 56664

Device Capacity
{
Cylinders : 3339
Tracks : 50085
Blocks : 50085
MegaBytes : 2707
KiloBytes : 2771500
}

Device Configuration : RDF1+Mir

Device is WORM Enabled : No
Device is WORM Protected : No

SCSI-3 Persistent Reserve: Disabled

Dynamic Spare Invoked : No

Dynamic RDF Capability : RDF1_OR_RDF2_Capable

STAR Mode : No
STAR Recovery Capability : None
STAR Recovery State : NA

Device Service State : Normal

Device Status : Ready (RW)
Device SA Status : N/A (N/A)

Front Director Paths (8):
{
----------------------------------------------------------------------
POWERPATH DIRECTOR PORT LUN
--------- ---------- ---- -------- ---------
PdevName Type Type Num Sts VBUS TID SYMM Host
----------------------------------------------------------------------
Not Visible N/A EF 04A:0 N/A 000 00 022 N/A
Not Visible N/A EF 13A:0 N/A 000 00 022 N/A
Not Visible N/A EF 04B:0 N/A 000 00 022 N/A
Not Visible N/A EF 13B:0 N/A 000 00 022 N/A
Not Visible N/A EF 04C:0 N/A 000 00 022 N/A
Not Visible N/A EF 13C:0 N/A 000 00 022 N/A
Not Visible N/A EF 04D:0 N/A 000 00 022 N/A
Not Visible N/A EF 13D:0 N/A 000 00 022 N/A
}

Message was edited by:
MikeMac
Removed Symm S/N

dynamox · Answer

it's expected as this is a CKD device (Mainframe). My mainframe devices are Emulation type CKD-3390 and have nothing for Device WWN field.

xe2sdc · Answer

As Dynamox the Great already explained, "Device WWN" is typical of Fibre Channel environments .. thus not available in MF

OpenVMS (and VMS) uses Device WWN to detect multipathing at OS level (no need to install PowerPath with VMS)

-s-

xe2sdc · Answer

http://en.wikipedia.org/wiki/Count_Key_Data

it's IBM stuff ..

Windows, Linux, Solaris, HPUX, AIX and almost any other operating system you may think about use FBA (fixed block architecture) .. Each disk is something like a big store where you can store your data in fixed blocks (a sector is 512 bytes). When you want your data you need to know the block number. Just supply the block to your disk and it will give back your beloved data...

With CKD it's a different story .. You still have a big store .. but it hosts tracks (something between 52 and 56 kb) and you can stuff different things in each track since you prepend your data with a key (that you can use to identify content) and with a pointer to next content in same track.. A lot different from our beloved filesystems

naren23-3_uew · Answer

Thanks dynamox and stefano for your reply.

What do you mean by CKD device? since i am new to this configuration.

Can you please tell which documents i have to refer to get clear idea of CKD device and how it its configured.

And also is there is any other sym device which will not have device wwn populated like ckd device.

xe2sdc · Answer

Unfortunatly I'm not a MF guru .. However in MF (MainFrame) world you have Escon and Ficon .. While both Escon and Ficon are quite different from SCSI and Fibre Channel, they share something.

I don't really know Ficon, however in Escon world (just like in good old SCSI world) you only need to map devices. As long as you map devices on SA or EA and connect your cables, the host will see devices.

I suspect that Ficon is almost the same as Fibre Channel (you need zones) but you don't have masking. So I suspect that you need only to map devices on EF (Ficon Adapter) and create zones on directors.

Message was edited by:
Stefano Del Corno

xe2sdc · Answer

Solution Enabler manuals 6.5 have a section named 'Mapping CKD devices' that may help you ..

naren23-3_uew · Answer

Thx for the explanation.

How do you assign the sym ckd device to the host. It is same as assigning the sym dev (i.e lun in FC scnario) to the host.

In the symmask table we can see see the mapping of sym device to the portwwn of the HBA.......

Can you please refer to any document where it explains assigning ckd device to the hosts.

MikeMac1 · Answer

Naren23, was your question answered? If so, can you please mark as answered and award points as you see fit so that others will know which answer(s) helped you. Thank you.

Symmetrix

Device WWN is NULL or empty

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