Hi all, I'm testing IO performance. My cluster consists of 4 nodes connect to 1 block-device using iSCSI-Multipath. Block-device is formated in OCFS2 file system & mounted to nodes. My first problem: - If I use dd or iozone in single node => adapters network utilization in storage ~ 80% - 90% - But I use dd or iozone in all nodes => adapters network utilization in storage ~ 50% My second problem: I use iozone in all nodes - When write: allways exists 1 node in cluster not write, mean not concurrently write in all nodes. - But when read: all nodes concurrently read from block-device. Thanks for your help! Best regards.