Hi, We have two Sun X4100M2 x86 based servers with Solaris 10 11/06 installed. Both servers have dual-path SCSI HBAs installed and connected to a StorEdge 3120 SCSI JBOD Array. I've successfully installed Oracle Clusterware and ASM with the proper disk group configuration. But when it comes to creating the database, both servers had crashed with "got external SCSI bus reset" errors in the /var/adm/messages files. After an investigation, i've seen that our vendor had installed the SCSI array with a single-bus topology, which only permits only one host to do I/O requests towards the array simultaneously. The only solution seems to change the topology to a dual-bus (split-bus) )one. But i've a couple of questions in my mind. 1. Do we need two HBAs for each host in order to form a dual-bus topology? Or is it enough to connect the same dual-path HBA's different ports to the array? 2. Is it supported to run Oracle RAC in a dual-bus SCSI topology with a JBOD array? 3. Has anyone successfully used StorEdge 3120 in a RAC installation and how? Note: Array is just a JBOD and doesn't have any controllers on it. We also don't need any hardware or software RAID configuration. While reading the documentation of StorEdge 3120, i've found the dual-bus topology in the link below. Can you say if it is suitable for RAC or not? http://docs.sun.com/source/816-7956-15/ch04_cable.html#pgfId-1000241 Thanks for your help. It would be appreciated. Best regards.