Notice to reader : real questions are hidden in this obfuscated message ! I'll mark them with ** to augment the chances for them being answered :) Path checker maintainers, ** would you object to my changing the checkers open() flags from O_RDWR to O_RDONLY ? ** Directio and readsector0 would not object, and all other checkers use the file descriptor to submit SG_IO ioctls which do not require Write capability. Re-reading the SG documentation at http://sg.torque.net/sg/sg_io.html, I understand it should be ok. In real life, scsi_id does exactly that for example. The particular issue I'm facing is that on a RHEL5 box presented with EMC Symmetrix R2 Logical Units (write-protected LU receiving SRDF updates from R1 LU), the checker bails out on open(/dev/sd?, O_RDWR| O_NONBLOCK) returning EROFS. opening with O_RDONLY grants us a usable fd, which give the checker a chance to report the actual path state. I'd like to fix the checker inconsistency, but we'll hit another wall short after that : because the device mapper refuses to honor the R2-multipath-tables loading without the read-only devmap option. This behavior is new to RHEL5. R2 LU could perfectly be multipathed in RHEL4. ** Does someone have insight about this new kernel behaviour, and about the multipath layer desired behaviour in this context ? ** I personnaly would rather not care for promoting a devmap from RO to RW upon R1-R2 split, and the even more tricky demoting from RW to RO (what about io flush ?) upon un-spliting. Regards, cvaroqui -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
