A while back I wrote on VMware and ALUA path preferences.. well the info is good, it is just that with vSphere 5 they decided to change the commands around a bit.  Here are the updated commands:

Here is the command to set the default path preference (once again change VMW_SATP_ALUA_CX to your type of storage (this example is for EMC Clariion / VNX with failover type 4 (alua) enabled):

esxcli storage nmp satp set –default-psp VMW_PSP_RR –satp VMW_SATP_ALUA_CX

Ok so the preference is set, how do you change existing paths that were added before the change to the default type?

for i in `ls /vmfs/devices/disks | grep naa.6006`;

do esxcli storage nmp device set –device $i –psp VMW_PSP_RR;done

In this example you see the “grep naa.6006” 6006 is specific to EMC type storage so as this is written it will change all EMC luna presented and exclude other lun types (for example LSI storage which is naa.600a) now to get all of the luns just change the 6006 to 600 and you should be done.