In this post, I will explain to you about "How to Identify Pure Storage Flash Array LUNs on HP UX". I will cover, How to extract unique wwn id in Pure storage flash array using CLI and GUI and match it on HP UX host
I decided to write this article because I have implemented the Pure Storage array recently for one of my clients and it was bit different then EMC or other vendors. My HP UX sysadmin was having issues in LUN identification, So thought of documenting it.
Table of Contents
How to identify LUN traditionally with EMC Storage array
Traditionally, whenever you Run "inq" utility/command in HP UX, then you get Device details, vendor and Unique WWN ID.
So you can approach a Storage admin, get WWN ID of LUN, match it with your "inq" output and you are done. Generally, Sysadmin matches two attributes out of three, LUN ID, LUN Size and WWN ID. This identification really becomes very important during reclamation of LUNs to avoid any downtime, due to wrong LUN reclamation.
For example, the image shown is from one of the HP UX servers and showing LUN details of Symmetrix, Vplex and Pure Flash array.
If you notice, WWN ID of Symmetrix and VPLEX are unique and it's easy to identify LUNs on HP UX host. But all Pure Storage "Flash Array" LUNs are showing same WWN ID.
This generally happens, if you are using Pure storage first time in your environment and you don't know about LUN serial numbers. In our case also, our HP UX sysadmin was confused and asked for help.
Just make a note of scsimgr command output in the image. it's different to WWN id number shown for /dev/rdisk/disk10 (EMC VPLEX).
root@TestHPUX # inq
I hope, problem statement is clear to you now, let's deep dive to find solution.
How to extract LUN serial number in Pure storage
So, in case of Pure storage, the first thing you need to understand LUN serial number, you can call it the same as LUN WWN ID numbers. These are also unique for each LUN across the storage. In our case, it was more important to get a unique serial number as our Pure Storage flash array is configured as active-active.
So, as Storage admin, if you are handling Pure storage first time, Getting a LUN serial number is not tough actually. Below mentioned steps can help you to get that.
Extract Pure storage Flash array LUN serial number using CLI
Enter IP of Pure storage array and select port as 22
Enter "username" and "password" on login screen
Once you are inside Pure Flash array storage console, Run "Purevol -list " command.
You just have a look at the screenshot. The first column depicts LUN Name, then second shows Size and then Date-Time. Finally, in the last column, you can get the serial number of LUNs.
Once you have extracted required Unique serial numbers for LUNs provisioned, now time to share it with Unix admin. Just make a note of highlighted Serial number ending with "33F" to match it on Unix.
How to find Pure storage Flash array LUN serial number using GUI
If you are not a CLI lover, you can extract LUN serial number using PureStorage GUI also. For that, you just need to go to Storage - Volumes - Select volume - go to the Details section. Then, you will find the serial number for required provisioned LUN.
Match Serial number on HP UX host
Now, when the storage part is done, you need to match this serial number and size of LUN on the HP UX host. Below mentioned simple steps can help you to match and identify LUN on HP UX host
Make a note, as explained, inq command won't show the serial number of Pure Storage Flash array correctly.
Login to HP UX host
Run "scsimgr" command.
root@TestHPUX # scsimgr get_attr -D "Device name" -a serial_number
It will give you serial number of provided device. Then you can match it with serial number provided by Storage admin.
If you are not interested in scrolling long output, you can just grep "current" to get serial number as shown in example.
root@TestHPUX # scsimgr get_attr -D "/dev/rdisk/disk10" -a serial_number | grep -i current
Now to make it easy for you, I have highlighted this serial number ending with "33F" in "Step 4" also in the storage section.
Now you have got the Serial number and also matched the LUN Size. Then you don't need to worry about it as replicated or active-active LUN. You will have the same serial number across both HP UX nodes, in case of the cluster.
Updated on 30-Dec-2020 :-
Latest version of inq utility "(Version V9.2-2602 (Rev 0.0)" now provides serial number of PURE LUN in output. So you can either run inq utility or scsimgr command to identify Pure flash storage LUN. Check out in comment section for details shared by one of my reader.
If you are habitual of traditional LUN WWN ID and recently purchased a New PURE flash storage array. Also, wondering How to find and match LUNs, especially on HP UX. Hope my post on "How to Identify Pure Storage Flash Array LUNs on HP UX" will help you.
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Check out Pure Storage Flash array recommended settings for HP UX.