topic Re: lun comment field question in Network and Storage Protocols

lun comment field question

wnorthmtitsd — Thu, 05 Jun 2025 07:03:22 GMT

Does anyone know the maximum size of the lun comment field ?

thanks!

----- walter

Re: lun comment field question

ekashpureff — Wed, 15 Dec 2010 17:12:12 GMT

I don't see it specified in the documentation. Might guess 255 chars.

We'll be doing SAN in class today - I'll see if a student wants to try and test it in a lab !

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff
ekashp@kashpureff.org
Fastlane NetApp Instructor and Independent Consultant
http://www.linkedin.com/in/eugenekashpureff http://www.kashpureff.org/

(P.S. I appreciate points for helpful or correct answers.)

Re: lun comment field question

wnorthmtitsd — Wed, 15 Dec 2010 21:48:59 GMT

Thanks Eugene.

I quit testing it after 100 but was curious.

---- walter

Re: lun comment field question

ekashpureff — Wed, 15 Dec 2010 22:12:18 GMT

I've tested to 640 characters so far with out breaking it !

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff
ekashp@kashpureff.org
Fastlane NetApp Instructor and Independent Consultant
http://www.linkedin.com/in/eugenekashpureff http://www.kashpureff.org/

(P.S. I appreciate points for helpful or correct answers.)

Re: lun comment field question

ekashpureff — Wed, 15 Dec 2010 22:15:00 GMT

sim1> lun show -v
    /vol/mnstrsan/luns/lun0      3.0g (3224309760)    (r/w, online, mapped)
        Comment: "Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP.Now is the time for the community to test the LUN comment field in Data ONTAP."
        Serial#: nBM6goZzNSIR
        Share: none
        Space Reservation: disabled
        Multiprotocol Type: windows
        Maps: monster=0
sim1>

( Eugene is sometimes easily amused ! )

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff
ekashp@kashpureff.org
Fastlane NetApp Instructor and Independent Consultant
http://www.linkedin.com/in/eugenekashpureff http://www.kashpureff.org/

(P.S. I appreciate points for helpful or correct answers.)

Re: lun comment field question

ekashpureff — Wed, 15 Dec 2010 22:20:10 GMT

It looks like the max length for a single run on command is 1024 characters. Longest I got was about 1024 less the 'lun comment /vol/lun/lu0' string...

I hope this response has been helpful to you.

At your service,

Eugene E. Kashpureff
ekashp@kashpureff.org
Fastlane NetApp Instructor and Independent Consultant
http://www.linkedin.com/in/eugenekashpureff http://www.kashpureff.org/

(P.S. I appreciate points for helpful or correct answers.)

Re: lun comment field question

fjohn — Fri, 07 Jan 2011 12:58:37 GMT

I used the Data ONTAP PowerShell toolkit to make a short script and test setting the LUN comment attribute in increments of 64 from 64 to 32768 characters long. The answer is it succeeded, so at least 32768 characters. The script I used was to test was:

Import-Module DataONTAP
Connect-NaController FAS3040A

$TestPattern ="XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
$TestString = ""
Do { $TestString = $TestString + $TestPattern ; set-NaLunComment /vol/testvol/qt_test/test.lun $TestString ; $TestResult = get-NaLunComment /vol/testvol/qt_test/test.lun ; $TestResult.Length } Until ($TestResult.length -eq 32768)

You could increase the test value of 32768 in the do - until loop to something higher and continue testing if you're really curious...