Multipath slow to create mapper files
 

We're running Oracle linux 5.9 and on one server within a 2 node Oracle RAC cluster, multipath mapper files take a whole 6 minutes after the local disk files to be created. The other server creates the files at the same time (or at worst a minute later) as the local disk.

Anyone have any ideas on this one?

Oracle support are telling me to put in a delay for Oracleasm so the files are created before the app starts (and after the mapper files are available) - this isn't a fix of course so I've rejected it.

Thanks.

Is the hardware on both servers the same? If so have you compared the multipath.conf between the two servers? Are you perhaps excluding local disks on the one that is doing it quickly but not excluding them on the other one. Have you set multipath rules to create specific names in in /dev/mpath and /dev/mapper?

Are the udev rules the same on both?

Actually I found the solution to this. There was a small SD card within the servers with the issue and on boot up, multipath was erroring that it couldnt create a mapper file for that device path so I excluded this SD card path within the multipath config file, rebooted and hey presto. All fixed.