------- Comment From [email protected] 2016-04-15 16:42 EDT------- (In reply to comment #27) > Meanwhile, with kernel 4.4.0-18 and installler version 447, the situation is > different: > While the problem originally occured in installer, is happens now, when the > target system is being IPLed. > > The "switch" (to avoid the word "reason") is the kernel module scsi_dh_alua. > When scsi_dh_alua is loaded, the auto LUN scanning upon activating a zfcp > device with NPIV LUNs causes that not all LUNs are detected. I assume, that > not the kernel module itself is the problem, but t seems to trigger the > problem. > > A very easy way to reproduce this is as follows: > have a system installed with kernel 4.4.0-18 (almost GA). Have two NPIV > enabled zfcp adaptors (on different PCHIDs) that can access the same (few) > LUNs each. Then: > > root@s8330005:~# lscss |grep 1732/03 > 0.0.1905 0.0.0012 1732/03 1731/03 80 80 ff 60000000 00000000 > 0.0.1945 0.0.0013 1732/03 1731/03 80 80 ff 61000000 00000000 > root@s8330005:~# lsmod |grep scsi_dh > root@s8330005:~# chccwdev -e 1905 > Setting device 0.0.1905 online > Done > root@s8330005:~# lszfcp -D > 0.0.1905/0x50050763070845e3/0x4082405300000000 0:0:0:1079197826 > 0.0.1905/0x50050763070845e3/0x4083405300000000 0:0:0:1079197827 > 0.0.1905/0x50050763070845e3/0x4084405300000000 0:0:0:1079197828 > 0.0.1905/0x50050763070845e3/0x4085405300000000 0:0:0:1079197829 > root@s8330005:~# lsmod |grep scsi_dh > root@s8330005:~# modprobe scsi_dh_alua > root@s8330005:~# chccwdev -e 1945 > Setting device 0.0.1945 online > Done > root@s8330005:~# lszfcp -D > 0.0.1905/0x50050763070845e3/0x4082405300000000 0:0:0:1079197826 > 0.0.1905/0x50050763070845e3/0x4083405300000000 0:0:0:1079197827 > 0.0.1905/0x50050763070845e3/0x4084405300000000 0:0:0:1079197828 > 0.0.1905/0x50050763070845e3/0x4085405300000000 0:0:0:1079197829 > 0.0.1945/0x50050763071845e3/0x4082405300000000 1:0:0:1079197826 > /sbin/lszfcp: line 244: > /sys/bus/ccw/drivers/zfcp/0.0.1945/host1/rport-1:0-0/target1:0:0/1:0:0: > 1079197827//hba_id: No such file or directory > /sbin/lszfcp: line 245: > /sys/bus/ccw/drivers/zfcp/0.0.1945/host1/rport-1:0-0/target1:0:0/1:0:0: > 1079197827//wwpn: No such file or directory > /sbin/lszfcp: line 246: > /sys/bus/ccw/drivers/zfcp/0.0.1945/host1/rport-1:0-0/target1:0:0/1:0:0: > 1079197827//fcp_lun: No such file or directory > 0.0.1945/0x50050763071845e3/0x4082405300000000 1:0:0:1079197827 > root@s8330005:~# > > When a zfcp attached SCSI LUN is used for installation, (almost?) all > scsi_dh modules are loaded upon activation of the zfcp device. This causes > some LUNs not to be detected. > If I get acces to that system an blacklist the scsi_dh_alua module, the IPL > works as expected ( i.e. all the LUNS are detected properly).
Hello, I just wanted to add to Thorsten's comment: we are also still working on analyzing this bug. To the best of my knowledge, the ALUA device-handler is not to blame here, like Thorsten also already suggested. After looking at debug-data collected during reproductions, it seems like a SCSI-Command sent by the ALUA device-handler gets lost and thus causes a timeout after one Minute. This then causes the SCSI-scan to abort. Its not yet known what causes this, but I have not found any indication, that it is caused by parts of the Linux kernel (including our zFCP driver). I am still investigating this and when I find anything substantial, I gonna update this bug. Also, we can't disable the ALUA device-handler completely - even if that sounds like a possible fix/workaround -, because storage-products like the IBM Storwize v7000 or the IBM SAN Volume Controller use those commands. It might be an individual workaround though, depending on the storage used. ** Tags removed: bugnameltc-139096 severity-high -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1567602 Title: FCP devices are not detected correctly nor deterministically To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1567602/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
