PowerEdge 6450 connecting to a Dell PowerVault 660 SAN

Basil Hussain basil.hussain at kodakweddings.com
Fri Aug 1 03:40:01 CDT 2003


Hi,

> > Does any one have some information on configuring LUNS so that a RedHat
> > Linux 7.2 can use them?   I am having trouble finding the information I
> > need to do this.

> one thing you may need to do is either recompile your kernel to
> probe all luns or use a boot time flag to get it to do so.

There is absolutely no need whatsoever to re-compile the kernel to get
RedHat Linux to scan for LUNs. All you need to do is add the following line
to your modules.conf:

options scsi_mod max_scsi_luns=255

Then you need to rebuild your initrd. See this RedHat doc for details:

http://kb.redhat.com/view.php?eid=392

All that the kernel compilation option for 'probe all LUNs' does is simply
change the default for the max_scsi_luns parameter, as evidenced by this
snippet I found in the Linux kernel docs:

> max_scsi_luns=
> -------------------
>
> Syntax: max_scsi_luns=<n>
>
> Sets the maximum number of LUNs (logical units) of SCSI devices to
> be scanned. Valid values for <n> are between 1 and 8. Default is 8 if
> "Probe all LUNs on each SCSI device" was selected during the kernel
> configuration, else 1.

Pay no attention to the stated maximum value of 8. Two separate RedHat docs
I found say to set it to either 128 or 255. Anyway, the modinfo description
for that parameter says "should be between 1 and 2^32-1", so I guess it's
whatever the system will handle.

Regards,

Basil Hussain
---------------------------------------
Internet Developer, Kodak Weddings
E-Mail: basil.hussain at kodakweddings.com




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