The simple scripts in /etc/xen/scripts which manage networking are fine for most usages, however, when your server is using bonding together with VLAN tagging (802.11q) you should consider an alternative. A PDF document written by Mark Nielsen, GPS Senior Consultant, Red Hat, Inc (I lost the original link, sorry) named “BOND/VLAN/Xen Network Configuration” as a…
There is a major confusion among DBAs regarding how to setup raw devices for Oracle RAC or Oracle Clusterware. This confusion is caused by the turn RedHat took in how to define raw devices. Raw devices are actually a manifestation of character devices pointing to block devices. Character devices are non-buffered, so they act as…
I have had a system panicking when running the mentioned below configuration: RedHat RHEL 4 Update 6 (4.6) 64bit (x86_64) Dell PowerEdge servers Oracle RAC 11g with Clusterware 11g EMC iSCSI storage EMC PowerPate Vote and Registry LUNs are accessible as raw devices Data files are accessible through ASM with libASM During reboots or shutdowns,…
I have demonstrated how to hot-add LUNs to a Linux system with Qlogic HBA. This has become irrelevant with the newer method, available for RHEL4 Update 3 and above. The new method is as follow: echo 1 > /sys/class/fc_host/host/issue_lip echo “- – -” > /sys/class/scsi_host/host/scan< Replace "<ID>" with your relevant HBA ID. Notice - due...
I have encountered it on several cases. RedHat Linux ES, by default, uses smp kernel which is limited to eight cores, or two sockets. You find out that your multi-socket hardware, with its 16 (or more…) cores show you only the first eight, both by the simple method of running ‘top‘ and then pressing on…
This is not a simple task, as there are few things which should actually happen for it to work. First – the switch port should support vlan tagging (of course, right?) I have used vlan2 for “external” network, and vlan3 for “internal” network. My configuration looks like this: ifcfg-eth0: DEVICE=eth0 BOOTPROTO=none ONBOOT=yes MASTER=bond0 SLAVE=yes ISALIAS=no…
