Networker

Re: [Networker] finding fibre devices on linux

2008-11-28 15:02:28
Subject: Re: [Networker] finding fibre devices on linux
From: Tim Mooney <Tim.Mooney AT NDSU DOT EDU>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Fri, 28 Nov 2008 13:58:23 -0600
In regard to: [Networker] finding fibre devices on linux, mark wragge said...:

Hi, I have presented some devices to a Linux server over a SAN. The
devices are not being found using probe-all and inquire. I know that on
a solaris server i have to configure some files to tell the OS to scan a
higher number of targets and luns. Do i need to configure a similar file
in Linux.

The answer is "it depends".

The version of linux is RH 2.6.9-55 Elsmp x86

Ok, you're running an outdated version of the kernel from Red Hat
Enterprise Linux 4.  That narrows things down a bit.

What type and model SAN HBA are you using?  Assuming it's still in the
dmesg ring buffer, can you provide the part of the buffer where it reports
about the HBA and what's connected to it, i.e. run dmesg and reply with
the part that starts where the HBA is found up to the point where it's
done finding devices on that HBA.  It might also be useful to see the
contents of /proc/scsi/scsi.

Are the devices that are missing on separate SCSI IDs, or are they
distinct LUNs on the same SCSI ID?  I would expect they're probably LUNs,
but it has an impact on how you get things to show up, so it is important.

Also, if the missing devices are on distinct LUNs, is there a gap in
LUN numbers between the devices that do show up and the ones that don't?
This is commonly referred to as "sparse LUNs", and if you Google on that
term you'll get a lot of hits without necessarily getting any clarity for
how to address the problem for your kernel version and distribution.  ;-)

If you reply with that information, I (or someone else from the list) can
probably help you out.  It might be Monday before I respond though.

If you're interested in doing some reading in the meantime, Google for
sparse luns, "rebuild initrd", and one or more of the tokens from

        options scsi_mod max_luns=15 default_dev_flags=0x040

Tim
--
Tim Mooney                                             Tim.Mooney AT ndsu DOT 
edu
Enterprise Computing & Infrastructure                  701-231-1076 (Voice)
Room 242-J6, IACC Building                             701-231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

To sign off this list, send email to listserv AT listserv.temple DOT edu and type 
"signoff networker" in the body of the email. Please write to networker-request 
AT listserv.temple DOT edu if you have any problems with this list. You can access the 
archives at http://listserv.temple.edu/archives/networker.html or
via RSS at http://listserv.temple.edu/cgi-bin/wa?RSS&L=NETWORKER

<Prev in Thread] Current Thread [Next in Thread>