Hi, We've bought and IBM BladecenterH and IBM DS4700 storage. We are using Redhat Enterprise Linux 5 and we are trying to put multipath working. RHEL5 we are using uses 2.6.18-8.1.3.el5xen. We've ported rdac patch (http://kernel.org/pub/linux/kernel/people/agk/patches/2.6/2.6.21/dm-mpath-rdac.patch) to RHEL5 kernel. We've also updated multipath-tools to support mpath_prio_rdac. Our multipath.conf is: devnode_blacklist { devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*" devnode "^hd[a-z]" devnode "^cciss!c[0-9]d[0-9]*" #USB 4G Flash drive inside HS21 devnode "sda" } defaults { multipath_tool "/sbin/multipath -v0" udev_dir /dev polling_interval 5 default_selector "round-robin 0" default_getuid_callout "/sbin/scsi_id -g -u -s /block/%n" #default_prio_callout "/bin/true" failback immediate path_checker rdac hardware_handler "1 rdac" prio_callout "/sbin/mpath_prio_tpc /dev/%n" path_grouping_policy group_by_prio } multipaths { multipath { wwid 3600a0b8000320bea0000048f46e52137 alias client_data } } When we start multipath -v2 it creates multipath devices. I can see 2 active paths (active controler) and 2 ghost paths (standby controler). When i unplug 2 active fibre that connect the fabric to DS4700, multipath reports I/O errors and doesn't failover the controler. Any ideas? Thanks for any help Nuno Fernandes -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel