how do we determine I/O channel seperation is possible

[Santhosh.H]

In ioscan -f cmd how do we determine buses refering the Hardware path field

[Santhosh.H]

my server has 2HDD. The HW Path is
0/0/1/1.15.0 & 0/0/2/1.15.0
can any one explain in more depth about reading the hw path

[Sridhar Bhaskarla]

Hi Santosh,

Two flags in ioscan will help you in understanding the paths.

ioscan -f > ioscan.out
ioscan -fnC disk > disk.out

ioscan -f will give you detailed description of each component, You will find like

ext_bus 2 0/0/2/0 c720
875 Ultra Wide Single-Ended
target 4 0/0/2/0.2 tgt
disk 1 0/0/2/0.2.0 sdisk

0/0/2/0 is the controller address - c
2 is the target - t
0 is the LUN (Scsiid of the disk) - d
So the combined address

SO this will make the device file c2t2d0

You can also do an lssf on /dev/dsk/c2t2d0 to find the information.

Look for the corresponding device in ioscan -fnC disk output.

-Sri

[Sanjay_6]

Hi santosh,

Try these two links,

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=ea0da3dd02263b732d/screen=ckiDisplayDocument?docId=200000046785420

http://us-support3.external.hp.com/cki/bin/doc.pl/sid=ea0da3dd02263b732d/screen=ckiDisplayDocument?docId=200000051933874

Hope this helps.

Regds

[Helen French]

Hi Santosh,

In ur server:

1) 0/0/1/1.15.0 - '0/0/1/1' is the controller address, '15' is the SCSI id of the disk, '0' is the LUN number.

2) 0/0/2/1.15.0 - '0/0/2/1' is the controller address, '15' is the SCSI id of the disk, '0' is the LUN number.

See this for some information about hardware addressing:

http://us-support.external.hp.com/cki/bin/doc.pl/sid=d3223f600c564ffc9d/screen=ckiDisplayDocument?docId=200000009825652

Also check 'man ioscan' and Hardware addressing topic in www.docs.hp.com

HTH,
Shiju

[Santhosh.H]

My two internal HDD device names are c1t15d0 and c3t15d0. this means the first is on controller 1 and the other on controller3 hence I/O channel seperation is possible. Any one conforms this first will gain 10 points closing this case. I expected some one to ask directly what is this device name and could had replied with the solution is possible and explination.

[thinphony]

u can conform that use the following text I cited from HP docs.
the c#t#d#[s#] syntax used in default device special files derives from ioscan output: c# is the card instance for the ext_bus class of
interface card to which the device is attached, t# is the target (SCSI address) of the disk device on the interface, d# is the device unit number.s# specifies section number and is provided for backward compatibility;
the device file addresses the entire disk (s0) when s# is unspecified. (See the disk (7) manpage.)

thinphony.

[Sridhar Bhaskarla · Accepted solution]

Santosh,

Confirmed. The number associated with C determines the instance number that is unique to each controller. So, in your case, there are two controllers and Yes channel seperation is possible.

-Sri