how locate phisical disk(s) on a c#t#d# device?

[Paolo Gilli]

I have an HP-UX 9000N with a disk array configured with FC60 and 6 SC10 in full bus cabling.
In /dev/dsk i found:
# ls -l
brw-r----- 2 bin sys 31 0x001000 Feb 4 2000 c0t1d0
brw-r----- 1 bin sys 31 0x016000 Jan 26 2000 c1t6d0
brw-r----- 1 bin sys 31 0x026000 Jan 26 2000 c2t6d0
brw-r----- 1 bin sys 31 0x050000 Feb 4 2000 c5t0d0
brw-r----- 1 bin sys 31 0x050100 Feb 4 2000 c5t0d1
brw-r----- 1 bin sys 31 0x050200 Feb 4 2000 c5t0d2
brw-r----- 1 bin sys 31 0x050300 Feb 4 2000 c5t0d3
brw-r----- 1 bin sys 31 0x050400 Feb 4 2000 c5t0d4
brw-r----- 1 bin sys 31 0x050500 Feb 4 2000 c5t0d5
brw-r----- 1 bin sys 31 0x050600 Feb 4 2000 c5t0d6
brw-r----- 1 bin sys 31 0x050700 Feb 4 2000 c5t0d7
brw-r----- 1 bin sys 31 0x051000 Feb 4 2000 c5t1d0
brw-r----- 1 bin sys 31 0x051100 Feb 4 2000 c5t1d1
brw-r----- 1 bin sys 31 0x051200 Feb 4 2000 c5t1d2
brw-r----- 1 bin sys 31 0x051300 Feb 4 2000 c5t1d3
brw-r----- 1 bin sys 31 0x052000 Feb 4 2000 c5t2d0
brw-r----- 1 bin sys 31 0x053000 Feb 4 2000 c5t3d0
brw-r----- 1 bin sys 31 0x070000 Feb 4 2000 c7t0d0
brw-r----- 1 bin sys 31 0x070100 Feb 4 2000 c7t0d1
brw-r----- 1 bin sys 31 0x070200 Feb 4 2000 c7t0d2
brw-r----- 1 bin sys 31 0x070300 Feb 4 2000 c7t0d3
brw-r----- 1 bin sys 31 0x070400 Nov 23 2001 c7t0d4
brw-r----- 1 bin sys 31 0x070500 Dec 14 2001 c7t0d5
brw-r----- 1 bin sys 31 0x070600 Dec 14 2001 c7t0d6
brw-r----- 1 bin sys 31 0x070700 Dec 14 2001 c7t0d7
brw-r----- 1 bin sys 31 0x071000 Feb 4 2000 c7t1d0
brw-r----- 1 bin sys 31 0x072000 Feb 4 2000 c7t2d0
brw-r----- 1 bin sys 31 0x073000 Feb 4 2000 c7t3d0
brw-r----- 2 bin sys 31 0x001000 Feb 4 2000 cdrom
(EOF):
how can I locate phisical disk(s) on the c#t#d# device?

Thank

[Leif Halvarsson_2]

Hi
In most disk arrays the scsi-adress depends of the slot-number (ex. the first slot is adress 0, second 1 aand so on, check the documentation of your array).
If there is a LED which show disk activity you can use "ioscan /dev/rdsk/c7t0d0" and see which disk is "blinking". In this case there must be no other activity on the disks (unmount if possible).

[Vincent Farrugia]

Hello,

Use dd:

dd id=/dev/dsk/c#t#d# of=/dev/null bs=64k

The disk which lights the LED up is it.

HTH,
Vince

[Quin Hammes]

I assume that you are using raid (0,1,0+1 or 5) since you have a fc60 therefore each of these device files does not represent a single disk rather a raid group. Are you directly connected to the fc60 or are you going through a hub or switch? If you have multiple connections to the fc60 then you should be seeing twice as many device files than raid groups (i.e. anything c5txdx should have a corresponding c7txdx but that does not hold true with your output so its a little confusing). Could you let me know how you have this wired? Your output would make more sense then.

Quin

[Kevin Addison · Accepted solution]

Paolo,

The FC60 is an array and as such you only see the luns from within unix. You will have two fibres connected to the FC60 you will therefore see every lun twice (two paths). It is still possible to find which disks the lun is configured on. But this may be two or more disk mechanisms.

Firstly use ioscan -fnCdisk|more to see all your device files with their related hardware paths.

Take the path of the device file you want to find and convert this to a lun. It will be similar to 0/2/0/0.8.0.4.0.0.2 if it is directly connected to the N Class or 0/2/0/0.4.20.0.0.0.2 if connected via a switch.

To convert the path to a lun ignore everything except the last three digits this is the lun number in "volume set address format".

To decode these convert the three numbers into binary using 1 bit for the first number then 4 bits for the second number and 3 bits for the last number. i.e 0.1.2 = 0 0001 010
Convert this to decimal = 10 This is the lun number.

Now to eventually find the physical drives the lun in on use.

#amdsp -i
this will give you a list of FC60 device numbers
#amdsp -a [long number display in last command]|more.

From here you can see which disk numbers relate to your lun number. The first number is the SC10 number ( add 1 to rotary switch
number on the back of the SC10 ) i.e 1:8 is in SC10 switch number 0.

The second number is the disk number. On full bus the disk numbers in every SC10 are from left to right
x:0 x:8 x:1 x:9 x:2 x:10 x:3 x:11 x:4 x:12
x being the SC10 number .

An easier way is to use "tool - info" from mstm this gives you a graphical representation of the disk locations.

Sam displays them differently.

Remember the lun may span several disks depending on the raid level.

Kevin

[Paolo Gilli]

In my question I forgot to describe the disks configuration.
As Quin and Kevin correctly wrote, I have the disks configured in LUN(3,5,6 disks), raid 5, directly connected to the fc60 .

With Kevin replay I have solved any problem.

Thank to all for your suggestions.