Hello all, Sorry if this is a stupid question. I deploy both HP MC/SG linux edition and RHCS for our customers. I just wondered why the latest RHCS remove quorum partition/lock lun with the new fencing mechanisms(powerswitch,iLO/DRAC, SAN switch....)? Lots of our customers choosed HP's sophisticated MC/SG linux edition for their mission critical system in Two Node Cluster Configuration. From our monthly health check service and customers' feedback, i do think HP SGLX is reliable and stable, even under heavy I/O traffic, the lock lun(quorum disk) works pretty good. And the whole cluster architecture is simple and clean, at same time means less issue and problem . I do think Redhat's product team is strong and obviously have their solid reasons to choose new mechanisms in RHCS v4. I've investigated and i can understand that quorum disk/lock lun in two node cluster configuration "Might Bring" more latency and impact the cluster but according to my previous words, i'm sure that it is pretty stable to use lock lun/quorum partition of HP SG/LX even under heavy I/O loads. I have no intention to start a comparison between HP SGLX and RedHat RHCS, All i want to get clear is quorum disk/lock lun Vs RHCS's new fencing mechanisms. Regards, Jun