I ran into this under RHEL4 and it turned out to be udev and the capi20 declaration. I commented the declaration out in 50-udev.rules (as well as the capi/%n) and started seeing my sd node appear (i.e. device 68:0). -- Bob -----Original Message----- From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi-owner@xxxxxxxxxxxxxxx] On Behalf Of Vinay Venkataraghavan Sent: Wednesday, January 09, 2008 5:31 PM To: Andrew Vasquez Cc: James Bottomley; linux-scsi@xxxxxxxxxxxxxxx; Matthew Wilcox Subject: Re: Number of devices that SCSI can support Thank you all for responding. While I agree that the scsi stack in linux should be capable of supporting many targets, I still see this problem all the time. It seemed to consistently happen on /dev/sdbm which corresponds to the 65th lun or target. My SAN configuration consists of: 4 targets with 16 luns each = 4 * 16 = 64 total devices. But I ran another test by changing my targets information and saw this issue for /dev/sdbm As mentioned on this thread, I am attaching some more information. Looks like SCSI inquiry is going through, and the inquiry succeeds. As you can see from the attached message below the /sys/class/scsi_device file also gets created: at /sys/class/scsi_device/1\:0\:3\:15/device/ and below this we find all the related entries such as: block/ dump queue_depth state delete generic/ rescan timeout detach_state model rev type device_blocked power/ scsi_level vendor So from this information it looks like the scsi mid layer had detected that particular lun. But the /dev/sdbm device has not been created. It was also mentioned that it could be a udev problem. The other curious issue is that if take the major number and the minor number from this entry and manually create the device file as such: mknod /dev/sdbm 68 0 it works after I rescan all the targets and luns and I am able to perform I/O on this lun. Any other ideas. Thanks, Vinay ----- Original Message ---- From: Andrew Vasquez <andrew.vasquez@xxxxxxxxxx> To: Vinay Venkataraghavan <raghavanvinay@xxxxxxxxx> Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>; linux-scsi@xxxxxxxxxxxxxxx; Matthew Wilcox <matthew@xxxxxx> Sent: Wednesday, January 9, 2008 7:49:33 AM Subject: Re: Number of devices that SCSI can support On Wed, 09 Jan 2008, Matthew Wilcox wrote: > On Wed, Jan 09, 2008 at 09:05:52AM -0600, James Bottomley wrote: > > On Tue, 2008-01-08 at 19:22 -0700, Matthew Wilcox wrote: > > > On Tue, Jan 08, 2008 at 04:55:46PM -0800, Vinay Venkataraghavan wrote: > > > > Is there a limit on the number of devices that SCSI supports. In other words, I have a QLogic HBA card, and I am connecting to a SAN which has 64 targets. > > > > > > I've personally had over five hundred LUNs. You shouldn't be hitting a > > > limit here. > > > > I believe the largest test that's been run was the old OSDL CGL > > workgroup ... they went up to 4096. > > > > However, LUN support depends on the driver and HBA parameters as well > > (some choose to have arbitrary limits). > > I was using a qlogic HBA for my tests, so I don't think this is the > problem -- although the original poster claims to have 64 targets, and I > had only one target with 128 luns (attached 4 times). > > -- > Intel are signing my paycheques ... these opinions are still mine > "Bill, look, we understand that you're interested in selling us this > operating system, but compare it to ours. We can't possibly take such > a retrograde step." Not sure what's going on as well, perhaps some logs could help... But the inbox qla2xxx driver in RHEL4 set's an HBA's scsi_host->max_id count to 512 (also verified with several test rings), so there shouldn't be a problem handling 64 distinct targets (FC ports). - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html ________________________________________________________________________ ____________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
