On 14-02-10 01:06 PM, Jeremy Linton wrote:
On 2/10/2014 5:11 AM, Hannes Reinecke wrote:
EVPD page 0x83 is used to uniquely identify the device. So instead of
having each and every program issue a separate SG_IO call to retrieve this
information it does make far more sense to display it in sysfs.
Tested-by: Jeremy Linton <jlinton@xxxxxxxxxxxxx>
So, I just ran it in 3.14-rc2. No OOPS, that is good. It even survived
probing a SPC-2 device without a page 0x83.
I tested it with a fairly narrow set of devices, a couple IBM libraries with
LTO/359x and a VTL.
I did notice this on an old IBM raid adapter running in the machine
cat: ident_lun_scsi_name: Invalid argument
(that came from this device)
sg_inq --page=0x83 --hex /dev/sg2
VPD INQUIRY, page code=0x83:
00 00 83 00 48 01 03 00 08 50 01 0b 90 00 12 1d 90 ...H....P.......
10 61 93 00 08 50 01 0b 90 00 12 1d 8e 61 94 00 04 a...P.......a...
20 00 00 00 01 61 a3 00 08 50 01 0b 90 00 12 1d 8d ....a...P.......
30 63 a8 00 18 6e 61 61 2e 35 30 30 31 30 42 39 30 c...naa.50010B90
40 30 30 31 32 31 44 38 44 00 00 00 00 00121D8D....
And there may be a couple descriptors missing here and there. For example
3592E05 is missing the total port count (I think).
VPD INQUIRY, page code=0x83:
00 01 83 00 5c 02 01 00 24 49 42 4d 20 20 20 20 20 ...\...$IBM
10 30 33 35 39 32 45 30 35 20 20 20 20 20 20 20 20 03592E05
20 30 30 30 30 30 37 38 33 36 33 32 33 01 03 00 08 000007836323....
30 50 05 07 63 02 41 0c 2c 01 13 00 08 50 05 07 63 P..c.A.,....P..c
40 02 81 0c 2c 01 14 00 04 00 00 00 02 01 23 00 08 ...,.........#..
50 50 05 07 63 02 41 0c 2c 01 24 00 04 00 00 00 01 P..c.A.,.$......
/sys/class/scsi_tape/nst14/device # ls ident_*
ident_lun_naa ident_lun_t10 ident_port_naa ident_port_relport ident_target_naa
This almost seems like a case where exporting the raw 0x83 data may be better...
I have seen corrupted "di" VPD pages as well. So the
order in which you look for designators can be important
(and whether you stop on the first error or continue).
$ sg_vpd -e -p 0x83
Matching standard VPD pages:
di 0x83 Device identification
di_asis 0x83 Like 'di' but designators ordered as found
di_lu 0x83 Device identification, lu only
di_port 0x83 Device identification, target port only
di_target 0x83 Device identification, target device only
The difference between --page=di and --page=di_asis is that the
first looks for lu, followed by port, followed by target device
matches. The --page=di_asis prints out the designators as they
are found. Finding and decoding anything beyond a corrupted
designator is hit or miss.
Also, as I stated previously, my personal bias is to include the page 0x80
serial number data for tape devices as well. That seems to be the most
reliable. Mostly because a lot of the VTLs now just give you the same
wwnn/wwpn in 0x83 for multiple LUNs. Meaning you can't uniquely identify the
device over different physical ports.
I'm guessing that various companies selling target
capable chips also provide generic target code for those
chips. Then it is up to the OEM to customize that generic
code for their devices. Some do that customization more
thoroughly than others.
Doug Gilbert
The IBM devices are nice in that they export a T10 Vendor ID with the
man/model/serial in 0x83, but that is not common in my experience.
For example (old T10k)
VPD INQUIRY, page code=0x83:
00 01 83 00 20 01 03 00 08 50 01 04 f0 00 93 ac f6 ... ....P.......
10 01 13 00 08 50 01 04 f0 00 93 ac f7 01 14 00 04 ....P...........
20 00 00 00 01 ....
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