what is Inquiry utility (INQ)?

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So what is INQ?

Inquiry utility (INQ) is a command-line troubleshooting utility that displays information on storage devices, typically Symmetrix. By default, INQ returns the device name, Symmetrix ID, Symmetrix LUN, and capacity. This utility will operate independently of any other EMC software.Use the INQ Utility to collect system information to provide to EMC Global Services for problem troubleshooting.

But we generally use EMC grab report for that?

Yes ,even INQ is also one of several tools bundled and run as part of the host grab utilities (EMC Grab and EMCReports).

 Can we analyze INQ output?

Luckily we can analyze INQ output. below is the process. Generally we see two types of INQ output. It is Enginuity level dependent.

for older versions INQ output will be in below format

When running inq or syminq, you’ll see a column titled Ser Num. This column has quite a bit of information hiding in it.

Device                          Product                         Device

—————-        ————————-       ——————————–

Name                    Type    Vendor  ID              Rev     Ser Num         Cap(KB)

—————-        —–   ——- ———       ——- ———       ——–

/dev/dsk/c1t0d0                 EMC     SYMMETRIX       5265    73009150        459840

/dev/dsk/c1t4d0         BCV     EMC     SYMMETRIX       5265    73010150        459840

/dev/dsk/c1t5d0         GK      EMC     SYMMETRIX       5265    73019150        2880

/dev/dsk/c2t6d0         GK      EMC     SYMMETRIX       5265    7301A281        2880

Using the first and last serial numbers as examples, the serial number is broken out as follows:

73      Last two digits of the Symmetrix serial number

009     Symmetrix device number

15      Symmetrix director number. If <= 16, using the A processor

0       Port number on the director

 

If Device Serial Number = “71018000” Legend = SSVVVDDP

SS = Last 2 Digits of System S/N V = Volume Number (000 – FFF) DD = Director Number (01 – 16 is A director, 17 – 32 is B

director) P = Port (0 – 3)

 

In new INQ outputs generally we can directly find columns for array SN and  device id and device WWN(i don’t have inq output from newe version so not posting it here)

 

what if I don’t have INQ utility and can get only multipathing output?

Yes. if mutlipathing output is from powerpath then we can directly get most of details

 

#powermt display dev=all ====>  Display All Attached LUNs

 

Mostly we used to run this command powermt, which will display all the attached logical devices to the server.

 

Pseudo name=disk915

Symmetrix ID=000290103691

Logical device ID=06B8

state=alive; policy=SymmOpt; priority=0; queued-IOs=0;

==============================================================================

————— Host —————   – Stor –   — I/O Path —  — Stats —

###  HW Path               I/O Paths    Interf.   Mode    State   Q-IOs Errors

==============================================================================

3 0/4/0/0/0/1.0x5006048c52a862e7.0x40a6000000000000 c14t4d6   FA  8cB   active  alive       0      2

3 0/4/0/0/0/1.0x5006048c52a862f7.0x40a6000000000000 c15t4d6   FA  8dB   active  alive       0      2

5 0/5/0/0/0/1.0x5006048c52a862e8.0x40a6000000000000 c16t4d6   FA  9cB   active  alive       0      2

5 0/5/0/0/0/1.0x5006048c52a862f8.0x40a6000000000000 c17t4d6   FA  9dB   active  alive       0      2

 

If I have only native multipathing?

So now we have to use a bit of technique to decode  device WWN which is part of CTD addressing

General EMC device  WWN: 600009700001926055542533030363338

you can break above wwn this way 60000970000 192605542 5330 30363338

192605542-serial nuumber of array in decimal

last 8 digits-30363338 are the symm device in ASCII

ASCII to Hexa

30=0

36=6

33=3

38=8

so device is 0638

so now we can say device is 0638 from array 5542

where exactly I can use this INQ or multipathing output ?

These outputs will be helpful for us in knowing what storage devices server able to see from san side. this can help us in resolving device missing or path down tickets.

 where do I get INQ utility?

Below is the FTP link

INQ utility

what else?

Yup, I am done :). If you have more info or any corrections please feel free to mail me..

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SAN QUES SET 01

dw-question-answer

1) what is FC controller and disk controller & disk array controller?
A. FC Controller is nothing but HBA (Host Bus Adapter)
The disk controller is the circuit which enables the CPU to communicate with a hard disk, floppy disk or other kind of disk drive.
A disk array controller is a device which manages the physical disk drives and presents them to the computer as logical units. It almost always implements hardware
RAID, thus it is sometimes referred to as RAID controller. It also often provides additional disk cache.

A disk array controller name is often improperly shortened to a disk controller. The two should not be confused as they provide very different functionality.

2) Difference and usage of RAID 0+1 and RAID 1+0
A)I don’t want to write answer again. There are already so many blogs explaining different raids and
there performance.

3)Default ID for SCSI HBA?
A) In a typical parallel SCSI subsystem, each device has assigned to it a unique numerical ID. As a rule, the host adapter appears as SCSI ID 7, which gives it the
highest priority on the SCSI bus (priority descends as the SCSI ID descends; on a 16-bit or “wide” bus, ID 8 has the lowest priority, a feature that maintains
compatibility with the priority scheme of the 8-bit or “narrow” bus).so answer is 7.

4) Highest and lowest priority in SCSI?
A) Each SCSI device is addressed on the bus via a specific number. For narrow SCSI (which allows up to 8 total devices), these are numbered 0 through 7; for wide SCSI
(16 devices) the numbering is 0 through 15. The priority that a device has on the SCSI bus is based on its ID number. For the first 8 IDs, higher numbers have higher
priority, so 7 is the highest and 0 the lowest. For Wide SCSI, the additional IDs from 8 to 15 again have the highest number as the highest priority, but the entire
sequence is lower priority than the numbers from 0 to 7. So the overall priority sequence for wide SCSI is 7, 6, 5, 4, 3, 2, 1 , 0, 15, 14, 13, 12, 11, 10, 9, 8.

5) SAN TOPOLOGY?
A) We have different types of topologies like core edge and mesh topology.

6) How many disks are minimum for Raid 5?
A) 3 disks are minimum for RAID 5.

7)Can Hotspare assigned for RAID0?
A) For Raid0 we don’t have any parity. so there is no point in assigning hot spare since we cannot rebuild data from failed disk.

8) What is HA?
A) HA means High Availbiliy.We do lot of things to maintain High Availbiliy in SAN like maintaining redundan fabrics, raid system, hot spares.
All these things help us in avoiding single point of failures and allows system to handle faults of failures.