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When looking at a storage adapter on a Fibre Channel network I see some different "naa" id:s for each LUN. For LUNs coming from the same SAN the naa seems similar, but still unique.

My first question is if the "naa" is based on anything physical on the discs or if it just an ID that the SAN attaches to each LUN as it is created?

Is it correct that a mpx name is something that a ESX host can produce when no naa is known?

The final question is of the SCSI id that could be seen from a LUN in the Storage Views in vCenter. There seems to be a SCSI id for each disk/LUN, and I wonder what does this SCSI id represent? If it was only a single disk it could perhaps be a physical serial number of the disk itself, but when looking at a LUN made up of several disks there must be something else.

When looking at a storage adapter on a Fibre Channel network I see some different "naa" id:s for each LUN. For LUNs coming from the same SAN the naa seems similar, but still unique.

My first question is if the "naa" is based on anything physical on the discs or if it just an ID that the SAN attaches to each LUN as it is created?

[] naa. id is from san lun, san storage should keep each lun unique,

Is it correct that a mpx name is something that a ESX host can produce when no naa is known?

[] correct, if san lun has not naa. id, ESX will generate such as mpx name

The final question is of the SCSI id that could be seen from a LUN in the Storage Views in vCenter. There seems to be a SCSI id for each disk/LUN, and I wonder what does this SCSI id represent? If it was only a single disk it could perhaps be a physical serial number of the disk itself, but when looking at a LUN made up of several disks there must be something else.

[] do you mean vml. id? vml. id is generated from naa. id, it can also include such as lun number and something else

Thank you for your reply!

naa. id is from san lun, san storage should keep each lun unique,

So this is generated for each LUN and should just be unique? It does not "mean" anything?

>correct, if san lun has not naa. id, ESX will generate such as mpx name

Is that common on a real SAN LUN, or is it mostly the local disks on the hosts?

>> The final question is of the SCSI id that could be seen from a LUN in the Storage Views in vCenter. There seems to be a SCSI id for each disk/LUN, and I wonder what does this SCSI id represent? If it was only a single disk it could perhaps be a physical serial number of the disk itself, but when looking at a LUN made up of several disks there must be something else.

>do you mean vml. id? vml. id is generated from naa. id, it can also include such as lun number and something else

It is this SCSI id numbers I am curious about:

What is the SCSI ID?

yeah, this SCSI ID should be vml id

binoche, VMware VCP, Cisco CCNA

The SCSI Name is the Page 83 ID of the LUN/disk and the WWN of the target.. On a disk, it will likely be the serial # of the disk. On an array, the array generates the serial number (usually according to a well defined method, but one that varies between every vendor and model).

--Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

Thanks! So the SCSI ID has no relation to the position of the disk on the SCSI bus or similar?

Do you know what use the SCSI ID has in ESX/ESXi, as the "naa" ID seems to be the primary id?

No relation to SCSI bus position.

the naa.XXX value is the Page 83 ID of the LUN itself. The SCSI ID is the WWN of the array concatenated with the LUN ID (aka WWN).

--Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

Wait, I thought that the WWN was somewhat equivalent with MAC addesses on ethernet and that the Storage Processor had the WWN address. Do you mean each SAN LUN has its own WWN?

Yes - each array LUN also has a WWN, in addition to each array TARGET (variously called, SP, processor, blade, etc) having a WWN.

--Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

Yes - each array LUN also has a WWN, in addition to each array TARGET (variously called, SP, processor, blade, etc) having a WWN.

Thanks!

So each LUN has the following?

a WWN address

a naa adress

a LUN id (or runtime name e.g. vmhba1:C0:T1:L20)

a SCSI ID

What is reason for this different forms av names/id?

All different ways to unqiuely identify.

the WWN is really the same as the NAA. The 'naa' value for the lun is 'naa.<WWN>'. The SCSIID is really just '<TARGETWWN><LUNWWN>.

The runtime name is an easier way to write things out (common nomenclautre for unix systems: controller:channel:target:lun).

-Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

All different ways to unqiuely identify.

For the vSphere Administrator, how much of this IDs do you normally have to understand? Will it typically be enough to see the excepted LUN id and then add a VMFS datastore to that, or do you need to understand how to match this IDs to different SAN arrays?

The runtime name is an easier way to write things out (common nomenclautre for unix systems: controller:channel:target:lun).

What does the "channel" number represent? I have mostly seen it as zero, can it be something else?

Its generally enough to just know the WWN for each LUN is unique.

Channel is an old SCSI reference - very rarely used these days, and, as you mention, is almost always '0'.

--Matt

VCP, VCDX #52, Unix Geek, Storage Nerd

Thanks a lot for your help with this.