Description of problem: When the wwid of a LUN ends in a digit and has partitions on it, kpartx will add p<numebr of partition> to the wwid. However, when the wwid ends in a letter, kpartx will just add the number, not the letter 'p'. This is causing some problems with SAN fabric changes. How reproducible: Set up LUNs in SAN, add partitions to them and check kpartx output Actual results: wwid that ends in digit get p<number> added, wwid that end in a letter get just the number added. Expected results: consistent output. Either always p<number> or always just <number> Additional info: Seems to be a problem with ATA namespace not allowing the letter-p<number> combination according to Heinz Mauelshagen.
Any more information on the <letters>-p<numbers> problem? This is a pretty easy issue to fix. It's just that i need an easy-to-distinguish partition delimiter. My personal prefernce would be <multipath_name>-p<partition_number> or <multipath_name>-part<partition_number>. I'd like to know if there is a problem with them, and exactly what else won't work. Switching the '-' for a '_' would be fine, if that is allowable. Just using <multipath_name>p<partition_number> works fine with the user_friendly_names option set, but it's hard to see appended on the WWID names. Also, Somebody needs to convince me that changing the naming scheme from U4 to U5 is a good idea, because it seems like a recipe for disaster to me. A better solution for RHEL4 would be to have the customers who are effected by this use the user_friendly_names option by adding user_friendly_names yes to the "defaults" section of their config file. This would force all multipath names into the mpath<number> format, which would mean that partitions would always look like mpath<number>p<partition_number>. If they need to make sure that the names are consistent across multiple machines, they simply need to copy the /var/lib/multipath/bindings file from a machine where multipathing has already been set up to the other machines that will access the same devices. This file holds the WWID to user_friendly_names bindings. That should fix the problem unless I am misunderstanding it. For RHEL5 I will make sure that there is a consistent delimiter.
There is now a consistent delimiter 'p'. If people need it to change, they must exit /etc/rc.sysinit and /etc/udev/rules.d/40-multipath.rules, and remove the "-p p" option from the kpartx command
As I said in Comment #1 and #2, this is fixed in RHEL 5. It will not be fixed in RHEL4, because it will break existing setups.