Hi guys, Iam using dm-multipath for a Infortrend dual controller F16F-R4031-6 FC system. Version details are : device-mapper-multipath-0.4.7-17.el5 device-mapper-1.02.24-1.el5 device-mapper-event-1.02.24-1.el5 OS : Red Hat Enterprise Linux Server release 5.2 (Tikanga) Kernel : 2.6.18-92.1.10.el5 #1 SMP x86_64 x86_64 x86_64 Recently, one of the RAID controllers failed and caused multipath to fail both active paths device-mapper: multipath: Failing path 8:32. sd 2:0:0:0: SCSI error: return code = 0x00020000 end_request: I/O error, dev sdd, sector 1976776672 device-mapper: multipath: Failing path 8:48. sd 2:0:0:0: SCSI error: return code = 0x00020000 end_request: I/O error, dev sdd, sector 1967432880 sd 2:0:0:0: SCSI error: return code = 0x00020000 end_request: I/O error, dev sdd, sector 161647296 This caused the ext3 filesystem to go into a read only mode. Full IO errors is at http://pastebin.com/m103325d9 The dual controller storage unit and the host server (Only 1 Server using 2 Qlogic FC HBAs) are hooked upto two different Qlogic SanBox FC switch for redundancy. multipath.conf : http://pastebin.com/m4c7da817 multipath -v4 -ll : http://pastebin.com/m7d863925 I have checked the logs on the FC switch and the HBAs and i dont see any event which suggest both paths failed at once. Even the errors i captured out of dmesg show that one of the physical disks that makes up dm-0 had 'end_request: I/O errors' while the other did not have any such error. sd 2:0:0:0: SCSI error: return code = 0x00020000 end_request: I/O error, dev sdd, sector 1967432880 sd 2:0:0:0: SCSI error: return code = 0x00020000 end_request: I/O error, dev sdd, sector 161647296 At this point iam wondering how paths 8:32 and 8:48 failed together - considering both paths are through two different FC switches. Any suggestions on this ? Additionaly, I have looked at the mailing list archives & annotated conf files and found two options a) failback and b) no_path_retry. What would be the best recommended values for these on a dual controller setup like mine ? It would also be helpful if someone could share infotrend specific settings multipath settings. TIA Dushyanth -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
