Hi, I am running two node active/passive cluster on RHEL3U8-64 bit operating system for my oracle database,both the nodes are connected to HP MSA-500 storage(scsi not Fibre channel) . Below are my hardware and clumanager version details. It was running fine and stable for last two years but all of a sudden for the past one month i am getting below errors on syslog and cluster restarting locally. Server Hardware: HP ProLiant DL580 G4 OS: RHEL3U8-64BIT INTEL EMT Kernel : 2.4.21-47.EL Storage : HP MSA-500 storage (scsci channel) Cluster Version: clumanager-1.2.26.1-1 redhat-config-cluster-1.0.7-1 NODE1 ip: 20.2.135.161 (network bonding configured) NODE2 ip: 20.2.135.162 (network bonding configured) VIP : 20.2.135.35 Syslog errors cluquorumd[1921]: <warning> Disk-TB: Detected I/O Hang! clulockd[1996]: <warning> Potential recursive lock #0 grant to member #1, PID1962 clulockd[1996]: <warning> Denied 20.1.135.162: Broken pipe clulockd[1996]: <err> select error: Broken pipe clulockd[1996]: <warning> Denied 20.1.135.162: Broken pipe clulockd[1996]: <err> select error: Broken pipe cluquorumd[1921]: <warning> Disk-TB: Detected I/O Hang! clulockd[1996]: <warning> Denied 20.1.135.161: Broken pipe clulockd[1996]: <err> select error: Broken pipe clusvcmgrd[2011]: <err> Unable to obtain cluster lock: Connection timed out cluquorumd[2100]: <err> VF: Abort: Invalid header in reply from member #0 cluquorumd[1934]: <err> __msg_send: Incomplete write to 13. Error: Connection reset by peer Can any one guide me what is this above error indicates and how to troubleshoot.After a long google search i found the below link from redhat that is matching my scenario.Can i follow the same because it is my very critical production server. https://bugzilla.redhat.com/show_bug.cgi?id=185484 Also anyone help me to configure a dedicated LAN (for example eth3) as heartbeat(private point to point cross over cable network for cluster communications),I don't wish heartbeat over public LAN , because of heavy Network saturation. Fot the above heartbeat configuration i didnot found any suitable document for rhel. Can any one provide me the suitable link or guide me what are all the changes i have to made in my existing cluster.xml file for this private heartbeat configuration to work. Waiting for some one reply its urgent for me Regards, Lingu