I think this question is regarding adding LUNs on a SCSI bus that have non-consecutive numbers. SLES distros used to have this scsi_sparselun option so you could scan if there was a LUN 1 and 5 but no LUNs numbered 0, 2, 3, and 4 for example. Also, RHEL 3/4 distros used to only support 1 SCSI device per target out-of-the-box.
As Daniel says, RHEL 5 distros don't require any modprobe.conf changes to support multiple scsi devices per target -- the default max_luns number seems to be 512 as of 5.1. Some RHEL 4 distros may require the "options scsi_mod max_luns=128" to be added to modprobe.conf and the ramdisk re-created. Also, I have not tried this lately, but there is a default_dev_flags option to scsi_mod that is available to let you scan for "sparse" or non-consecutive LUN numbering schemes at boot time. I'm not entirely sure what this value would be (since I don't have a way to try), but I suspect it would be something like default_dev_flags=0x240. I'm also not clear on what the default is for all RHEL kernel versions. If /sys is to be believed, the default is to not scan for SPARSE LUNs at boot time. Now as to scanning for these LUNs on a running system, we use the ubiquitous rescan-scsi-bus.sh script with the "--nooptscan" option and I can hot-add non-consecutive LUNs to my system. Hopefully, this is useful. If someone has tried any "default_dev_flags" configuration, I'd love to hear about it. On Feb 10, 2008 11:30 PM, Zavodsky, Daniel (GE Money) < [EMAIL PROTECTED]> wrote: > I have not had any issues with multiple LUNs in RHEL 5.1 (I have tried > up to 128 LUNs per target) > > Regards, > Daniel > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ben > Sent: Friday, February 08, 2008 4:34 PM > To: RHEL5 mailing list > Subject: [rhelv5-list] Non-zero LUNs > > Earlier versions of Linux had issues with multiple LUNs. Are there any > issues we should be aware of in RHEL 5.1 with non-zero numbered LUNs? > > e.g. > > Host: scsi7 Channel: 00 Id: 02 Lun: 01 > Vendor: SUN Model: T4 Rev: 0302 > Type: Direct-Access ANSI SCSI revision: 03 > > is an entry from /proc/scsi/scsi for a volume exported from a Sun SAN > (StorEdge 6320). > > There is no > > Host: scsi7 Channel: 00 Id: 02 Lun: 00 > > Will this cause any issues? > > Ben > > _______________________________________________ > rhelv5-list mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/rhelv5-list > > > > _______________________________________________ > rhelv5-list mailing list > [email protected] > https://www.redhat.com/mailman/listinfo/rhelv5-list > -- Dave Costakos mailto:[EMAIL PROTECTED]
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